A citation style glossary

Citation terms explained in plain English

Image credit: TeroVesalainen on pixabay

As a university student, you’re expected to adhere to citation style guidelines for your papers – but that can be difficult if you’re not familiar with all of the terminology.

While all styles agree on the principles behind citation, they can vary tremendously on what information should be included and how it should be formatted. Of course, you want to adhere to the rules and use them in your paper. But how can you do that if you don’t even know what the terms in your guidelines mean?

The following glossary can help. It contains some common terms you’re likely to hear from your professors or encounter in your style guidelines, as well as some that are less common but which you might encounter in your reading.



Annotated bibliography

A bibliography that contains additional information, typically the author’s comments, on each work.


The citation style of the American Psychological Society is one of the most widely used author-date citation styles. The current version is the 6th edition.

Author-date method

A parenthetical form of citation that requires in-text citations to include the author and year, for example "(Miller 2013)".

Bibliographic information

Information about a source, such as its author, title, publisher, etc. The entries in a bibliography contain bibliographic information so that the reader can find the source if desired.


Although this term is commonly used for the list of sources cited that appears at the end of a paper (or other work), it actually has a broader scope and can also include sources that were consulted but never cited.

It contains bibliographic information that the reader can use to find each source and is usually, but not always, sorted alphabetically.

To add to the confusion, there are also stand-alone bibliographies. These are often book-length publications that attempt to list all works on a particular topic, by a particular author, or with another shared characteristic. They are often annotated.


A Latin abbreviation meaning “compare” that is sometimes seen preceding citations when an author wants to point out a source or sources with differing viewpoints.


The citation is how you indicate that you’ve used content from another source and let the reader know who and where it has come from. The form can vary depending on what type of citation style you are using: author-date, footnote, or reference number. If a parenthetical citation is used, the full bibliographic information for the source will be found in the bibliography.


Citation style

The guidelines from a publishing company, journal, organization, or university department that lay out which bibliographic information should be included, the punctuation to be used, and the formatting of citations and bibliography entries.


Nearly obsolete. Abbreviation used for a male author or female author (respectively) when the name was repeated in the next footnote or in the same or next line of the bibliography (for example, if the author was the same as the editor of a book or if the author was repeated).


“Chicago” is a shortened way of referring to the “Chicago Notes and Bibliography” citation style, which is probably the most widely-used footnote style in the English-speaking world. Although used less often, there is also an author-date version of Chicago. The Chicago style is currently in its 17th edition.


Abbreviation for “Digital Object Identifier”. Unique identifier for an electronic article, for example, 10.1007/s11573-018-0916-6


Endnotes are similar to footnotes, but instead of appearing at the bottom of the page, they’re listed either at the end of the paper or, in a book, at the end of each chapter.

Et al.

Et al. is an abbreviation for the Latin term “et alii” and means “and others”. Many in-text citation styles use et al. to avoid having to list out more than one or two authors in a work written by many authors. This helps minimize a disruption of the reading flow.


Abbreviation for "the following page" or "the following pages". For example, “5f.” could be used for pages “5-6” and “5ff” could be used for multiple pages following page 5. Rarely used today, but you might encounter it in citations in older texts.

Footnote style

Footnote styles use a superscript number in the text which corresponds to a numbered note at the bottom of the page which contains the citation.

In contrast to a reference number style, each footnote has its own unique number, even if the same source is cited more than once.

Harvard method

A term primarily used outside of the United States, to refer to the author-date method of citation. There is no one definitive “Harvard” citation style.


Abbreviation for the Latin word “Ibidem”, meaning “in the same place”. Commonly used in footnote citation styles when the same work was cited in the preceding footnote or within the same footnote. The historical reason for using "Ibid." and other cross-reference abbreviations, such as "op. cit." and "loc. cit.", was to save space, paper, and printing costs.

In-text citation style

Blanket term for any citation style that uses citations in the text (as opposed to footnotes) regardless of their content or format. The most common type is the author-year format, but this type of citation style also includes reference number styles.


Abbreviation for “International Standard Book Number”. Unique identification number for a book.

Loc. cit.

A cross-reference to another footnote citation, similar to ibid or op. cit. Loc. cit. is used to refer back to both a work and a specific page number that were already cited somewhere in the text. For example, you might see “Votteler, op. cit.” and then a few pages back find the original citation containing the full bibliographic information and the page number. Both loc. cit. and op. cit. are no longer used as often, since they require the reader to do a lot more work and, in the digital age, they are no longer needed to save space and printing costs.  However, you might encounter these abbreviations in some of your sources.


The citation style of the Modern Language Association is one of the most commonly used citation styles among undergraduate students in the United States. It is a parenthetical citation style, but in contrast to APA or other Harvard styles, it does not use an author and date. Instead it only requires the author and page numbers in the in-text citations.

Op. cit.

A cross-reference to another footnote citation, similar to ibid. or loc. cit. Op. cit. is used to refer back to a previous citation of a work, but with a different page number. For example, you might see “Votteler, op. cit., p. 38”. A few pages back you might then find the original citation containing the full bibliographic information. While it’s not as widely used as it was in the past, you may encounter this abbreviation in some of your sources.


You are using a quotation when you place content from another source in your own text. Quotations can either be direct or indirect. A direct quotation is a word-for-word quotation and an indirect quotation, also known as a paraphrase, is when you restate the meaning of the quotation in your own words. Both types of quotations should always include a citation.


Another term for an indirect quotation.

Parenthetical citation style

A more narrowly defined term for an in-text citation style in which the citation appears in parentheses. Both the APA and MLA citation styles are parenthetical citation styles.

Reference list

Often used interchangeably with the term "bibliography", a reference list has a slightly narrower meaning in that it is a list only of the sources actually cited.

Reference number styles

Reference number styles are a form of in-text citation style but instead of using the author-date format, they use a number which refers to an entry in the bibliography. The numbers in the text can appear in superscript, in parentheses, or in brackets. The corresponding source information is never found in a footnote, but instead appears in a bibliography at the end of the document. The bibliography entries are usually sorted in the order the items were cited or alphabetically.

Secondary quotation

Secondary quotations are quotations that aren’t taken from the original source but from a citation in another source. See this blog post.

Short title

A shortened form of a title, which is sometimes used in footnote citation styles if a work was already cited in full in a previous footnote. Used in the Chicago Notes and Bibliography citation style.  


A source is any other work (book, article, webpage, etc.) that you use when writing your paper. It's important to always designate information from your sources wtih a citation.


A citation style closely based on the Chicago Notes and Bibliography style but specifically written for students writing academic papers or dissertations.

Works cited

A common heading for a reference list. The MLA citation style requires a list of “Works cited” at the end of a paper.


Are there other terms that are missing in our glossary that are unclear for you? We can help! Just let us know on our Facebook page!

Created by: Jana Behrendt – Published on: 7/30/2019
Tags: Beginning students Citation Good to know

About Jana Behrendt

Jana Behrendt, a librarian by training, is deeply interested in everything related to personal information management. However, she does not read as much as you would expect from a librarian. She loves hiking in the Swiss Alps – as long as she doesn’t have to look down.

Get a regular dose of research inspiration. Enter your email address to get bi-weekly emails whenever new content is added.