How to Cite an Encyclopedia or Dictionary Entry (APA, MLA, Chicago)

Knowing how to cite an encyclopedia or dictionary entry is a small skill that saves a lot of headaches, because reference works sit in an awkward spot: they are edited collections, often have no obvious author, and the online versions can change between the day you read them and the day you submit your paper. This guide walks through print and online reference works in APA, MLA, and Chicago, covers entries with and without a named author, and explains when you need a retrieval date for continuously updated online entries. If your source is the crowd-edited kind, see our dedicated Wikipedia citation guide, since it follows slightly different rules.

What counts as an encyclopedia or dictionary entry

A reference work is a source designed to be consulted in pieces rather than read straight through. That includes general encyclopedias (Britannica), subject encyclopedias (a handbook of psychology), and dictionaries (Merriam-Webster, the Oxford English Dictionary). In citation terms, each individual entry is treated like a chapter in an edited book: the entry is the part, and the encyclopedia or dictionary is the whole work that contains it. That single idea drives every format below, whether your copy is a heavy print volume or a webpage.

The two questions that change your citation are (1) is there a named author for the entry, and (2) is the online version continuously updated. Sort those out first, then pick your style. If you want to skip the manual formatting, you can drop the details into our APA citation generator and produce a clean entry in seconds.

Citing a print encyclopedia entry

Print reference works are the easiest case because nothing changes after publication, so you never need a retrieval date. You do need the edition, the editor (if listed), the publisher, and page numbers when the entry sits on specific pages of a volume.

Print entry with a named author

When an individual entry is signed, treat that person as the author and the encyclopedia editor in the “In” position, just as you would for a chapter. The example below uses invented details in the standard pattern.

Print entry with no named author

Many encyclopedia and especially dictionary entries are unsigned. APA then begins with the entry title (or treats the publishing organization as author), MLA begins with the entry title, and Chicago commonly cites well-known reference works in a note only. Here is a dictionary example with no author.

That “s.v.” in the Chicago note stands for sub verbo, Latin for “under the word,” and it is the traditional way to point a reader to a specific alphabetical entry. For more on sources without bylines, see our guide on citing a source with no author.

Citing an online encyclopedia or dictionary entry

Online reference works follow the same author logic but add a URL and, in some cases, a retrieval date. The most common modern example is an online dictionary. Use our MLA citation generator or Chicago citation generator if you want the formatting handled automatically.

Retrieval and access dates for continuously updated entries

This is the detail most students miss. An online dictionary or encyclopedia entry that changes over time, with no fixed publication or archived version, gets a retrieval date because the content you saw may not be the content a reader finds later. In APA 7th edition, that means using “n.d.” for the date when no specific date is shown and adding “Retrieved [date], from [URL]” only when the content is designed to change. If the page is dated or archived (a stable version), you drop the retrieval date and just give the URL.

MLA 9th edition does not require an access date, but recommends including one (“Accessed 7 June 2026”) for online sources that lack a clear publication date or that update frequently, which describes most online reference entries. Chicago similarly suggests an access date when no revision or publication date is available. The simple rule: if the entry can quietly change and offers no version stamp, give the date you read it. For the broader principle, see our notes on citing a source with no date and the general how to cite a website guide.

Common mistakes to avoid

A few errors show up again and again in reference-work citations:

Italicizing the wrong title

The entry title is never italicized. Italics go on the whole work, the encyclopedia or dictionary, not the individual word or topic you looked up. In APA that means sentence case for the work title; in MLA and Chicago it means title case.

Adding a retrieval date when you do not need one

Print works and stable, dated online pages never take a retrieval date. Reserve it for genuinely living, undated entries. Sprinkling “Retrieved” onto every source is a common APA error.

Treating the publisher as the author by default

Check for a signed author first. Many subject encyclopedias credit individual contributors, and crediting the right person matters for your in-text citations. Only fall back to the entry title or organization when no author is named.

Forgetting the edition and volume

Reference works are revised often, so the edition number is part of identifying exactly what you read. Multi-volume encyclopedias also need the volume number.

Putting it together

Once you can tell whether an entry has a named author and whether the online version is continuously updated, citing an encyclopedia or dictionary is straightforward in every style. Treat the entry like a chapter, italicize only the whole work, match capitalization to your style, and add a retrieval or access date only when the content can change without warning. For a deeper look at how the major styles differ overall, compare our APA format guide, MLA format guide, and Chicago style guide, or read the overview in citation styles explained. When you are ready to format yours, the free citation generator will build a correct reference and matching in-text citation for you.