Referencing glossary

This glossary explains common terms used in academic referencing and citation systems. Whether you’re editing a bibliography, checking citation accuracy, or learning how different styles work, these short definitions will help you understand the basics of referencing and reference editing.

This glossary will continue to grow as we add more terms related to referencing and academic publishing.

AMA

AMA refers to the American Medical Association citation style, widely used in medicine, health sciences, and clinical research. It uses the author–number system, where sources are cited with superscript or bracketed numbers (e.g., ¹) that correspond to a numbered reference list in the order of citation. AMA style includes specific rules for author names, journal title abbreviations, page ranges, and article formats. It differs from author–date styles like APA by prioritizing concise in-text citations and sequential numbering, making it well suited to scientific and clinical writing.

annotated bibliography

An annotated bibliography is a list of sources that includes a brief note or paragraph (an annotation) beneath each entry. The annotation typically summarizes the source, evaluates its credibility or relevance, and may explain how it was used in the research. Annotated bibliographies are often assigned in academic settings to help students engage critically with reading material and demonstrate understanding of the sources they plan to use.

APA

APA style is a referencing and formatting system created by the American Psychological Association. It is an author–date style (also known as a Harvard system), where in-text citations include the author’s surname and year of publication (for example, Smith, 2022). APA style is widely used in the social and behavioural sciences, including psychology, education, business, nursing, and linguistics, and is one of the most common referencing styles in academic writing.

Read our guide to APA.

author–date system

The author–date system (also known as Harvard) is a citation system where in-text citations include the author’s surname and the year of publication, for example ‘(Smith, 2022)’. Full details of each source then appear in an alphabetized reference list at the end of the document. This system is used in styles such as APA and is common in the social sciences, natural sciences, and many interdisciplinary fields.

author–number system

The author–number system (also known as Vancouver) is a citation system where sources are assigned numbers, and those numbers are used in the text instead of author names. The full source details appear in a numbered reference list, usually in the order sources are cited. In-text citations may appear in brackets (e.g., ‘(5)’ or ‘[5]’) or as superscripts (e.g., ‘⁵’). This system is used in styles such as AMA and IEEE, and is common in medicine, engineering, and the physical sciences, where concise citations and easy scanning of references are especially important.

author–page system

The author–page system is a citation system in which in-text citations include the author’s surname and the relevant page number, rather than the publication year. For example: ‘(Smith 56)’. This system is used in styles such as MLA, and is common in the humanities, where the precise location of a quoted passage is often more important than the date of publication. Full publication details appear in an alphabetized reference list or bibliography at the end of the document.

bibliography

A bibliography is a list of sources consulted or relevant to a piece of work, whether or not they were directly cited in the text. It can include background reading, recommended sources, or works that informed the research but were not quoted or referenced explicitly. This contrasts with a reference list, which contains only the sources that are cited in the text. Bibliographies are more common in humanities disciplines and in styles such as Chicago (notes and bibliography), while reference lists are typically used in author–date systems like APA and many scientific styles.

cf.

Cf. (from the Latin confer, meaning ‘compare’) is used in scholarly citations to direct the reader to another source for comparison, often one that offers a different perspective or related discussion. It differs from ‘see’, which points the reader to supporting material. Because cf. can be misinterpreted, many modern style guides recommend using clearer wording instead, such as ‘For a contrasting view, see…’. Capitalize cf. only when it begins a note or sentence.

Chicago

Chicago refers to the Chicago Manual of Style, a widely used style guide in the humanities and social sciences. It offers two styles: notes and bibliography, which uses footnotes or endnotes, and a bibliography; and author–date, which uses in-text citations with a reference list. The notes system is common in history, arts, and literature, while the author–date system is more typical in social sciences and sciences. Chicago provides detailed guidance not just on citation formats but also on grammar, punctuation, capitalization, and manuscript preparation.

Citation

A citation is a reference to a source used in a piece of writing. It appears in the text (for example, through an author–date system like (Smith, 2022), a numerical system like [5] or ⁵, or a footnote or endnote reference) and directs the reader to the full details of that source in a reference list, bibliography, or notes section. Citations acknowledge the original author’s work, support claims with evidence, and help readers locate the source for verification. A citation is different from a reference, which is the full publication detail listed at the end of a document.

citation system

A citation system is a method of showing sources within the text that links to full details elsewhere. The four main systems are: author–date (e.g., ‘Smith, 2022’), author–number (e.g., ‘[5]’ or ‘⁵’), author–page (e.g., ‘(Jones 56)’), and notes that use footnotes or endnotes (e.g., superscript numbers leading to notes). A citation system governs how you cite sources in the body of a document, whereas a reference style or style guide (such as APA, MLA, Vancouver, or MHRA) provides broader rules, including how to format the reference list or bibliography, punctuation, capitalization, and other presentation details.

common knowledge

Common knowledge refers to information that is widely known, easily verified, and undisputed, such that it does not require a citation. This includes well-established facts (e.g., water freezes at 0°C), widely recognized historical dates (e.g., the Second World War ended in 1945), or information that a typical reader in the field would be expected to know. What counts as common knowledge can vary by audience and discipline. When in doubt – especially with specialized facts, statistics, or interpretations – it’s safer to provide a citation.

Crossref

Crossref (https://www.crossref.org) is a non-profit organization that provides metadata for scholarly publications, including journal articles, books, conference papers, and preprints. Its database links DOIs (digital object identifiers) to authoritative publication details such as titles, authors, and publication dates. Crossref is widely used by publishers, libraries, and reference editing tools (like Thrix and Merops) to verify and complete citations. Because it’s updated directly by publishers, Crossref is one of the most reliable sources for current academic metadata, especially in science and technology fields.

direct quotation

A direct quotation is a word-for-word reproduction of text from a source, placed within quotation marks (or formatted as a block quote for longer passages). Direct quotations are used when the original wording is important for meaning, accuracy, or emphasis, and must be accompanied by an appropriate citation. A direct quotation differs from a paraphrase, which restates the same idea in new wording, although paraphrases must also be cited. Style guides vary in how they format direct quotations, including rules for punctuation and the use of page numbers.

dissertation

A dissertation is a major written project submitted for a university degree. In citations it is generally treated like an unpublished thesis, unless hosted in an institutional repository or published elsewhere. In the UK, the term usually refers to undergraduate or master’s research; in the US it typically refers to doctoral work. See thesis.

DOI

A DOI (Digital Object Identifier) is a permanent, unique identifier assigned to a published work such as a journal article, chapter, or dataset. It provides a stable link to the official version of the source, even if the website or URL changes. A DOI looks like 10.1038/s41586-020-2649-2 and can be turned into a direct link by adding https://doi.org/ in front, ensuring the reference remains easy to find and verify.

edition

An edition refers to a specific version of a published work, usually a book. New editions are released when the content has been revised, updated, or expanded – for example, to reflect new research or correct errors. Editions are typically numbered (e.g., 2nd ed., 3rd ed.), and academic citations should always specify the edition used, because page numbers and content may differ between versions. Editions are different from volumes, which are separate parts of a multi-volume work rather than updated versions of the same text.

ellipsis

An ellipsis (…) is a set of three dots used in writing to indicate that part of the text has been omitted, usually from a quotation. It shows that material has been removed without changing the meaning. Ellipses should not be used to alter the sense of the original passage or to misrepresent the author’s intent.

em dash / em rule

An em dash or em rule (—) is a long dash used to create a strong break in a sentence, often for emphasis or interruption. For example: The results were unexpected—and significant. In academic contexts, an em dash can act as a parenthetical dash or appear between a title and subtitle. Conventions differ: in the US, em dashes are typically written without spaces (word—word), while in the UK, a spaced en dash (word – word) is usually used instead. Em dashes are longer than en dashes, which are also commonly used for ranges (e.g., 23–45).

en dash / en rule

An en dash or en rule (–) is a dash slightly longer than a hyphen (-) and shorter than an em dash (—). It’s commonly used for ranges, such as page numbers (pp. 23–45) or dates (2019–2023), although some style guides (including AMA) use a hyphen for ranges instead. En dashes may also show a connection or contrast between equal terms (e.g., doctor–patient relationship). In the UK, a spaced en dash (word – word) is often used as a parenthetical dash or between a main title and subtitle, whereas in the US, an unspaced em dash is preferred.

endnote

An endnote is a note placed at the end of a chapter or document that provides a citation, comment, or clarification linked to the text. Endnotes are used in some academic styles as an alternative to footnote, offering the same information but consolidating notes away from the main text to create a cleaner page layout. Like footnotes, endnotes may be accompanied by a bibliography or reference list, depending on the style guide.

et al.

Et al. is an abbreviation of the Latin phrase et alia, meaning ‘and others’. It’s used in in-text citations and reference lists to show that a work has multiple authors without listing every name, typically after the first author (e.g., Smith, et al.). Some styles guides require et al. to be italicized, while others do not, and some style guides require a comma before it, while others do not.

f./ff.

f. and ff. are abbreviations sometimes used in references to indicate page ranges. f. means ‘and the following page’ (for example, p. 42 f. refers to pages 42–43), while ff. means ‘and the following pages’ (for example, p. 42 ff. refers to page 42 and several pages after, though the exact end point is unspecified). Because these abbreviations can be ambiguous and differ between citation traditions, most modern style guides recommend giving a clear page range instead (e.g., pp. 42–45) unless the style specifically allows or requires f. or ff.

footnote

A footnote is a note placed at the bottom (foot) of a page that provides a citation, explanation, or additional information related to part of the text. In style guides that use notes, such as Chicago (notes and bibliography) or OSCOLA, footnotes give source details and may be followed by a bibliography. Footnotes serve the same purpose as endnotes, but appear on the same page as the referenced content, making them easy for readers to consult without leaving the page.

grey literature

Grey literature refers to research and information that is produced outside traditional academic publishing and is not typically peer reviewed or formally indexed. Examples include reports from government agencies or NGOs, policy papers, theses, white papers, preprints, conference papers, and datasets. Grey literature can be valuable for up-to-date or specialized information, but it may vary in quality and accessibility, so it should be evaluated carefully and cited clearly when used in academic work.

hanging indent

A hanging indent is a formatting style in which the first line of a paragraph begins at the left margin and all following lines are indented. It helps readers clearly distinguish where each reference begins. Hanging indents are required in many academic styles – including APA and MLA – and are commonly used in reference lists and bibliographies. A hanging indent is especially important in numbered reference lists (such as Vancouver or IEEE), where indenting the lines after the citation number helps keep entries aligned and easy to scan.

Harvard

Harvard is another name for the author–date citation system, where in-text citations include the author’s surname and year of publication, e.g. ‘(Smith, 2022)’, with an alphabetized reference list at the end. Harvard is not a single style guide, and there is no single ‘official’ version – many institutions and publishers use their own variations. Styles based on the Harvard system include APA and certain versions of Chicago (author–date), as well as numerous university-specific guidelines.

ibid.

Ibid. is an abbreviation of the Latin word ibidem, meaning ‘in the same place’. It’s used in note citation systems, such as Chicago (notes and bibliography), to refer to the same source as the immediately preceding citation. For example, if two notes in a row cite the same book, the second may simply use ibid. instead of repeating the full citation. If referring to a different page in the same source, it may appear as ‘ibid., 45’.

idem

Idem is a Latin word meaning ‘the same’, used in some footnote-based citation systems to refer to the same author as the previous citation. It differs from ibid., which refers to the same source; idem specifically indicates that the author is the same, even if the source is different. For example, if two consecutive notes cite different works by the same author, the second may begin with idem. This usage appears mainly in older legal and humanities texts, and many modern style guides prefer repeating the author’s name or using a shortened citation instead.

in press

In press refers to a work that has been accepted for publication but has not yet been formally published. This means the content has passed peer review (if applicable) and is in the final stages of production, such as copyediting or typesetting. When citing a source listed as in press, the year may be replaced with ‘in press’ (e.g., ‘Smith, in press’) because a final publication date is not yet available. This term differs from preprint, which refers to work posted before formal peer review and acceptance.

in-text citation

An in-text citation is a brief reference placed within the body of a document to credit a source and point readers to the full entry in the reference list or bibliography. Different citation systems use different formats. In the author–date system (used by styles such as APA), an in-text citation typically includes the author’s surname and year, such as ‘(Smith, 2022)’. In the author–number system (used by styles such as AMA or IEEE), sources are cited with numbers in brackets or superscript, like ‘[5]’ or ‘⁵’. In the author–page system (used by MLA), citations usually include the author’s surname and page number, for example ‘(Jones 56)’.

ISBN

An ISBN (International Standard Book Number) is a unique ID assigned to books and other standalone publications. It distinguishes between titles and editions, and even formats (e.g., hardback vs paperback). Modern ISBNs have 13 digits (e.g., 978-3-16-148410-0), while older ones may have 10. Most citation styles do not require an ISBN in references. ISBNs differ from ISSNs, which are used for journals and other serial publications.

ISO 4

ISO 4 is an international standard for abbreviating journal titles, helping to ensure consistent and recognizable abbreviations across databases, reference lists, and indexing systems. For example, Journal of Biological Chemistry becomes J. Biol. Chem. under ISO 4 rules. ISO 4 is maintained by the International Organization for Standardization and is used by services such as the ISSN Centre and PubMed. ISO 4 differs from the NLM journal abbreviation standard.

ISSN

An ISSN (International Standard Serial Number) is a unique ID assigned to serial publications such as academic journals, magazines, and continuing series. An ISSN distinguishes a serial title from others with similar names, and print and online versions of the same journal may have different ISSNs. Most citation styles do not require ISSNs in reference lists, but they are commonly used in libraries, publishing, and indexing systems. ISSNs differ from ISBNs, which identify books and other standalone publications.

issue number

An issue number identifies a specific part of a journal volume, helping to locate where an article was published within that volume. Journals are typically organized by volume (often corresponding to a year) and then divided into issues (for example, monthly or quarterly releases). A reference may include volume and issue numbers, such as 15(3), meaning volume 15, issue 3. Not all journals use issue numbers (some publish articles continuously within a volume) but when they are present, citing them helps ensure precise and accurate referencing.

italicization

Italicization is the use of italic type to emphasize text or mark specific elements in writing. In academic referencing, italics are commonly used for book and journal titles, volume numbers in some styles, and scientific species names (e.g., Homo sapiens). Italics may also be used for foreign words, key terms on first use, or emphasis – though style guides differ on when and how italics should be applied. Italicization contrasts with quotation marks, which are often used for article or chapter titles, depending on the style guide.

periodical

A periodical is a publication issued at regular intervals, such as weekly, monthly, or quarterly. Periodicals include journals, magazines, newspapers, annual reports, and other serial publications. They publish content in recurring issues or volumes and often have an ISSN. In academic contexts, the term periodical is broader than journal: all journals are periodicals, but not all periodicals are journals. When citing a periodical, references typically include the title, volume, issue, date, and page range (if available).

journal

A journal is a type of periodical that publishes scholarly research, often peer reviewed, in specific academic disciplines or fields. Journal articles typically present original research, literature reviews, case studies, or theoretical discussions, and are organized into volumes and issues. Journals usually have an ISSN, and citations include the article title, journal title, volume, issue, pages, and (in many cases) a DOI. While magazines and newspapers are also periodicals, journals specifically focus on academic and professional research.

loc. cit.

Loc. cit. is an abbreviation of the Latin phrase loco citato, meaning ‘in the place cited‘. It was historically used in footnotes to refer to the same page of a work previously cited. For example, if a source had been quoted on page 42, a later note regarding that same page might read Smith, loc. cit. Like op. cit., this abbreviation is now considered outdated and is discouraged in most academic style guides, which instead recommend systems such as ibid. or a shortened citation that clearly identifies the work and page number.

MLA

MLA refers to the citation style developed by the Modern Language Association. It uses the author–page citation system, meaning in-text citations include the author’s surname and page number, for example ‘(Johnson 42)’, rather than the year. MLA is widely used in the humanities, especially in literature, languages, cultural studies, and related fields. Full publication details appear in an alphabetical reference list headed ‘Works Cited’ at the end of the document.

narrative-citation

A narrative citation is a form of in-text citation in which the author’s name is included as part of the sentence, with the publication year (and page number, if required) placed in parentheses. For example: Smith (2022) argues that…. Narrative citations help integrate sources smoothly into academic writing. They contrast with parenthetical citations, where all citation information appears in parentheses.

n.d.

n.d. stands for ‘no date‘ and is used in citations when a source does not have a single identifiable publication year. This may be because the date is not given, or because the content is continuously updated – for example, a webpage that changes over time rather than being published on a specific date. Instead of a year, citations use n.d. (e.g., ‘(Smith, n.d.)’). Some style guides recommend including an access date for online sources when n.d. is used.

NLM

NLM stands for the National Library of Medicine, the world’s largest biomedical library and part of the US National Institutes of Health. NLM maintains major research databases such as MEDLINE and PubMed, and provides authoritative journal metadata through the NLM Catalog. NLM also publishes its own style guide, called Citing Medicine, commonly used in medical and life-science writing. Importantly, NLM maintains its own standard for journal title abbreviations, which is widely used in biomedical publishing and differs in some cases from the international ISO 4 standard.

note citation system

The note citation system is a citation system in which sources are cited using numbered notes at the bottom of the page (footnote) or at the end of a document (endnotes). Each superscript number in the text corresponds to a note containing the source details. Some reference styles, such as MHRA (widely used in the humanities) and OSCOLA (used in UK legal writing), use full citations on first mention and shortened forms thereafter. Note systems are especially common in disciplines like history, law, and philosophy.

op. cit.

Op. cit. is an abbreviation of the Latin phrase opere citato, meaning ‘in the work cited‘. It was traditionally used in footnote-based citation systems to refer back to a source that had been cited earlier, without repeating full details. For example, after a full citation to a book, a later note might read Smith, op. cit. to point readers back to the previous entry. Modern style guides rarely recommend op. cit. because it can make references harder to follow; most now prefer shortened citations or systems like ibid. and idem, or simply repeating the author and a brief form of the title.

OSCOLA

OSCOLA (Oxford Standard for the Citation of Legal Authorities) is a citation style used primarily in UK legal writing and academic law publications. It uses the note citation system, relying on footnotes rather than in-text citations, and typically includes a bibliography. OSCOLA avoids punctuation and unnecessary formatting to keep references clean.

paraphrase

A paraphrase is a restatement of someone else’s ideas in your own words, keeping the original meaning but changing the language and structure. To paraphrase (verb) means to express the same idea differently, often to improve clarity or fit the flow of your writing. Paraphrased material must still be cited, because although the wording is original, the ideas are not. Paraphrasing differs from a direct quotation, which uses the source’s exact words, and from a summary, which condenses a larger section of text into a shorter form.

parentheses

Parentheses (singular parenthesis) are curved punctuation marks ( ), used to enclose information such as clarifications, examples, or citations without interrupting the main text. In academic referencing, parentheses are used for author–date citations, e.g. (Smith, 2022) or Smith (2022) and often around publication years in reference lists. Parentheses are a type of bracket, but they differ from square brackets [ ], which are typically used to insert editorial notes, corrections, or clarifications inside quoted text. Some citation styles also use parentheses around reference numbers, e.g., ‘(5)’.

parenthetical citation

A parenthetical citation places all citation details – such as the author’s name, year, and sometimes page number – inside parentheses at the end of a sentence or clause, e.g. (Smith, 2022). This format keeps the citation separate from the narrative flow of the text. Parenthetical citations contrast with narrative citations, where the author’s name appears in the sentence itself.

parenthetical dash

A parenthetical dash is a dash that separates additional information within a sentence, similar to parentheses, for emphasis or clarity. For example: The findings – although preliminary – are promising. In the US, em dashes are typically used without spaces (text—text), while in the UK, spaced en dashes are more common (text – text). In references, a related use appears in titles and subtitles, where a dash can separate a main title from the subtitle (e.g., An Introduction to Genetics – Concepts and Applications). Although this is not strictly ‘parenthetical‘, it follows the same typographic conventions.

personal communication

Personal communication refers to information obtained directly from an individual that is not publicly accessible or recoverable by readers. Examples include phone or video calls, in-person conversations, and private correspondence such as letters, emails, text messages, or direct messages. Because these sources cannot be retrieved or verified, most style guides say they should only be cited in the text, and not in the reference list. A typical citation might read: J. Smith, personal communication, 2024. Some styles require permission before citing personal communications.

plagiarism

Plagiarism is presenting someone else’s work, ideas, or words as your own without proper acknowledgement. It includes copying text directly without citation, paraphrasing without credit, reusing someone else’s structure or argument, or submitting work created by another person as original. In academic writing, plagiarism is a serious breach of ethical and scholarly standards and can result in penalties ranging from loss of credit to expulsion or retraction of published work. Proper citation and referencing help avoid plagiarism by giving credit to original authors and sources.

PMID

A PMID (PubMed identifier, or PubMed ID) is a unique numerical ID assigned to records in PubMed, the biomedical citation database maintained by the US National Library of Medicine. A PMID identifies a specific article indexed in PubMed and can be turned into a link by adding it to the PubMed URL, for example: https://pubmed.ncbi.nlm.nih.gov/12345678/.

preprint

A preprint is a version of a scholarly paper shared publicly before peer review or acceptance by a journal. Researchers often post preprints on dedicated servers such as arXiv or medRxiv to share findings quickly, receive feedback, and establish precedence. Because preprints haven’t been formally reviewed, they may change significantly before publication and shouldn’t be confused with works in press, which have already been accepted. If a final peer-reviewed version exists, it’s usually best to cite that instead, unless you need to reference information unique to the preprint.

primary source

A primary source is original material that provides direct evidence about a topic. It comes from the time or person being studied, such as research articles reporting new findings, historical documents, diaries, interviews, legal cases, datasets, or artworks.

private correspondence

See personal communication.

PubMed

PubMed is a free database maintained by the US National Library of Medicine, providing access to citations and abstracts for biomedical and life sciences literature. It includes records from MEDLINE, life science journals, and online books, and often links to full-text articles through publishers or open-access repositories. PubMed also assigns unique identifiers (PMIDs) to articles, making it easy to locate and verify biomedical research. Tools like Thrix and Merops use PubMed metadata to help ensure citations in medical and scientific fields are accurate and complete.

quotation marks

Quotation marks (“ ” or ‘ ’) are punctuation marks used to enclose direct quotations, and titles of shorter works (such as journal articles or book chapters) in many citation styles. Quotation marks contrast with italics, which are typically used for titles of longer works such as books and journals. Conventions vary by region: in the US, double quotation marks are standard, with single marks for quotations within quotations; in the UK, the pattern is usually reversed, with single marks used first and double quotation marks for nested quotations.

reference list

A reference list is a list of all the sources that are cited directly in the text of a document. Each entry corresponds to an in-text citation, allowing readers to locate the exact works referenced. This differs from a bibliography, which may include additional sources consulted for background reading or further context, even if they are not cited. Reference lists can be numbered (usually sequenced by the order they are cited in the text) or alphabetized by the first author’s surname.

retraction

A retraction is a formal statement issued by a journal or publisher to withdraw a previously published work from the scholarly record. Retractions occur when serious issues are discovered after publication – such as errors that invalidate the findings, plagiarism, ethical concerns, or data fabrication. A retracted article is usually marked clearly online and in databases, and a retraction notice explains the reason for withdrawal. Retraction is different from a correction, which amends a published paper without removing it. Detecting retracted sources is important for accurate scholarship, and tools like Thrix help flag them.

secondary reference

A secondary reference is a citation to a source that is discussed or quoted within another source, rather than one you consulted directly. For example, if Author A cites a study by Author B and you rely on Author A’s description instead of reading Author B’s work yourself, your citation to Author B is a secondary reference. Most academic style guides recommend avoiding secondary references when possible by locating and citing the original source, as relying on another author’s interpretation can introduce errors or misrepresent the original content.

secondary source

A secondary source interprets, analyses, explains, or summarizes one or more primary sources. Examples include review articles, textbooks, literature reviews, encyclopaedia entries, and scholarly essays discussing past research or historical events.

sentence case

Sentence case is a style of capitalization in which only the first word of a title or heading is capitalized, along with proper nouns. For example: The history of microbiology in Europe. Sentence case is used in styles such as APA for article and chapter titles in reference lists. It contrasts with title case, where most major words are capitalized.

sic

Sic is a Latin term meaning ‘thus’ or ‘so’, used in quoted text to show that an apparent error, unusual spelling, or odd wording is part of the original source and has not been introduced by the person quoting it. It’s typically placed in square brackets immediately after the original text (e.g., ‘The resarch [sic] was conclusive‘). Sic signals that the quotation is accurate, helping to avoid confusion.

style guide

A style guide is a set of rules that governs how written work should be presented, including grammar, spelling, punctuation, tone, capitalization, abbreviations, numbers, and document formatting. It may also cover citation and referencing conventions, helping ensure consistency across academic or professional writing. Well-known widely-used academic style guides include AMA, APA, Chicago, MLA, and OSCOLA.

supplement

A supplement is an additional issue or section of a journal that is published alongside the regular issues, often focusing on a special topic, conference proceedings, or sponsored research. Supplements are usually numbered or labelled (e.g., vol. 12, suppl. 2) and may have their own page numbering system. In references, the supplement number (or just the word supplement) should be included to help readers locate the source accurately. Supplements differ from regular issues because they are not part of the journal’s standard publication schedule and may follow distinct editorial or peer-review processes.

thesis

A thesis is a substantial research document submitted for a degree. In referencing, a thesis is usually treated as an unpublished academic work unless it has been formally published. Citation styles often require details such as the author, title, degree type, institution, and year, and may note whether the thesis is available online through a university repository. Usage varies by region: in the UK thesis typically refers to a doctoral work, while in the US it commonly refers to a master’s project. See also dissertation.

Thrix

Thrix (www.thrix.ai) is an online reference-editing tool made by Shabash Ltd that corrects, formats, and enhances citations and reference lists. It applies academic styles such as APA, MLA, Chicago, and Vancouver; checks metadata using sources like Crossref and PubMed; adds missing details; and ensures references are consistent. Thrix is designed for students, researchers, editors, and publishers who want fast, accurate reference formatting without manual checking.

title case

Title case is a style of capitalization in which the main words in a title are capitalized, while short function words such as and, of, or the are usually left in lowercase unless they begin the title. For example: The History of Microbiology in Europe. Title case is common in book titles and journal names, and is used in styles such as MLA and Chicago. It contrasts with sentence case, where only the first word and proper nouns are capitalized.

Turabian

Turabian refers to a student-oriented guide to using the Chicago citation style. Although Turabian provides simplified explanations and practical advice for formatting essays, theses, and dissertations, the editorial and citation rules are the same as those in the Chicago Manual of Style. Like Chicago, Turabian supports both notes-and-bibliography and author–date systems, mirroring Chicago, but focuses on the needs of student writers rather than professional publishers. The guide was developed by Kate L. Turabian at the University of Chicago.

URL

A URL (uniform resource locator) is the address used to locate a resource on the internet, such as a web page or online document. A URL tells a browser where to find content and how to retrieve it (for example, https://www.thrix.ai). In academic references, URLs are often used to cite webpages, online reports, and other digital sources that don’t have a DOI or other persistent identifier. Unlike DOIs, URLs can change over time, so style guides often recommend including accessed dates or using DOIs when available.

web page

A web page is a single page on a website, identified by its own unique URL such as https://shabash.net/merops/. Examples include a blog post, help page, or contact form within a larger site. When referencing online material, you would normally cite a web page rather than an entire website, because a page provides the precise location of the information being used.

website

A website is a collection of related web pages hosted under a single domain (for example, thrix.ai). It may contain articles, tools, images, and other resources, organized across multiple pages and sections. Some style guides (including APA) recommend not listing an entire website in the reference list. Instead, APA typically advises citing a specific web page when possible, or mentioning the website name in the text and providing the URL in parentheses if needed.

Vancouver

The term Vancouver is used in two related ways in academic referencing:

1. A citation system: an author–number approach where sources are cited in the text with numbers (e.g. [3] or superscript numbers), and the reference list is ordered numerically according to citation order. This system is widely used in medicine and the natural sciences and typically uses abbreviated journal titles and concise punctuation.
2. A specific style guide: the version formalized in Citing Medicine, the style guide published by the US National Library of Medicine (NLM). Many journals follow variants of Vancouver rules based on the original guidance developed by medical editors at a 1978 meeting in Vancouver, with later alignment by the ICMJE.

Vancouver differs from author–date style guides such as APA, where citations include the author and year and references are listed alphabetically.

volume

A volume is a numbered grouping of published material. In journals, a volume typically represents all issues published within a given year (for example, vol. 15 may contain multiple issues). In references, the volume usually appears before the issue number (if a journal uses them), such as 15(3), meaning volume 15, issue 3. Books can also be published in multiple volumes.