A Glossary in a Book: Purpose, Format, Examples
What is a glossary in a book, anyway? Do you need one in your book? And if so, how to format it?
To stop your head from spinning, drawing on my 7+ years as a nonfiction book copyeditor, I’ve compiled everything you need to know about book glossaries, with examples, below.
(I hit the highlights again at the end under the “Glossary format” heading.) Here we go!
What is a glossary in a book?
A glossary is an optional section, placed in a book’s back matter, that lists, defines, and explains unfamiliar or specialized terms used in the main text.
What is the purpose of a glossary in a book?
The purpose of a glossary is to provide succinct definitions of unfamiliar or specialized terms. But it’s also:
to save readers the time of looking up the terms elsewhere
to improve the flow of the main text by not having to interrupt it with definitions
to make the content more useful and accessible to the general public without having to dumb it down for more advanced readers
The purpose of a glossary is first and foremost to provide clear and concise definitions of terms that appear in the book, but as you can see, there’s more to it than just that.
What books need a glossary of terms?
If you’re wondering “Does my book need a glossary?”: No. A glossary is not required.
Scientific, technical, and academic books often have a glossary.
Nonfiction genres like How-To books, Health & Well-Being and Fitness books, Reference books, and Travel books sometimes include glossaries.
Fiction books occasionally have glossaries—especially science fiction and fantasy novels with unique world-building and, at times, historical fiction books.
According to Kevin Osworth, if you’ve written a book with “made up language, a plethora of cities and places with odd names, or a complex and rich history, [you] may opt to include a glossary to define words, places, or ‘historical’ events that are brought up in the book.”
Where is the glossary in a book?
Here’s where to find the glossary in a book: in the back matter (back matter meaning the back of the book).
The glossary goes after the acknowledgments and after any appendixes, but before any endnotes, bibliography, index, or about the author.
The image here shows where to put the glossary in a book. Not all books have or need to have all of these elements.
Some books also have pages asking for reviews, listing other books by the same author, or that prompt readers to take some sort of action; those can be inserted wherever it seems appropriate.
Every once in a while you’ll see a book with a glossary in the front matter, with the intention being that readers must know the definitions before they are to begin reading.
The Chicago Manual of Style (CMOS) says to put the glossary in the back matter.
Book glossary format and parts of book glossary
What does a glossary include? A title; an introductory paragraph (optional); terms; definitions, in alphabetical order and each separated by a blank line; cross-references (optional).
I’ll go through each component below, and recap it all at the end.
Here’s a sample format for your book glossary:
Title for a Glossary Section
The first element of any book’s glossary section is a title, styled the same as any other chapter headings.
Just title it Glossary, not Glossary of Terms, Glossary of Select Terms, or anything else.
Any time you refer to it in the main text, it should be lowercased and never in bold or italics. The same goes for the acknowledgments, introduction, chapter 1, bibliography, etc.
Does the glossary go in the table of contents? Yes. Include your glossary and its first page number in your table of contents.
“Occasionally, boldface may be used for key terms” in the text, especially in textbook, “to highlight terms that also appear [later] in the glossary,” instructs The Chicago Manual of Style.Introductory paragraph
➡️Some glossaries begin with a one- or two-paragraph introduction explaining what’s in the glossary.
This is optional—done occasionally.
A brief introductory paragraph or two can help explain what’s being defined or not being defined, and offers an opportunity to show the author’s humor and/or reflect the tone of the book.
Here is an example:
Terms and Definitions
“Words to be defined should be arranged in alphabetical order, each on a separate line and followed by its definition,” says The Chicago Manual of Style.
“Each entry consists of the term being defined and one or both of the following: a definition (or definitions) and a cross-reference to other entries in the glossary,” according to The Copyeditor’s Handbook.
➡️Put each term in bold. Do not capitalize or italicize a glossary term unless it consistently appears that way in the text.
➡️Then comes punctuation: a period, a colon, or an em dash, also in bold.
If you use a dash and you’re following AP style or non-US English, you may prefer a spaced en dash rather than an em dash. Don’t put a hyphen, spaced hyphens, double hyphens, or a tilde after the term.
➡️Next comes a cross-reference or the definition.
If you need to direct readers to a different term in the glossary, there will be no definition, so start with a cross-reference. You’ll only be doing this occasionally, if at all.
“If no definition appears, the cross-reference begins with See, which redirects the user to a more common synonym, a more generic (or more specific) term, or a variant spelling,” advises The Copyeditor’s Handbook.
Add See in italics and the other term in bold, followed by a bold period.
The Copyeditor’s Handbook advises this:
“Typically, a definition opens with a concise sentence fragment that captures the essence of the term being defined. Subsequent sentences in a definition may be fragments or grammatically complete; when a term has more than one definition, each definition begins with a concise sentence fragment.”
➡️The definition begins with a capital letter and runs anywhere from a few words to a few sentences, followed by a period.
If there are multiple definitions within an entry, each should be consecutively numbered, with the number in parentheses: (1) Definition one. (2) Definition two.
➡️A definition might be followed by one or more cross-references at the end.
This is optional.
The purpose of a cross reference at the end of a glossary entry is to direct the reader to one or more closely related or complementary entries to expand their knowledge and understanding.
The Copyeditor’s Handbook says this: “The cross-reference begins with See also, Contrast, or Compare (normally italicized unless what follows, e.g., a foreign language term, is in italics),” in which case Contrast or Compare would not be italicized.
Use cross-references sparingly.
➡️Finally, each glossary entry should end with a period. The only exception to that rule is if there are no cross-references and each definition is an incomplete sentence.
Get ready to publish a polished nonfiction book that is clear, concise, consistent, and that complies with industry standards (and/or have your glossary edited by a pro).
Or see digital downloads, courses and coaching services for getting published.
Book glossary indentation and spacing
CMOS instructs that glossary entries
have blank lines between them
appear in one column (“avoid multiple columns”)
can be formatted with no indentation; in “flush-and-hang style,” meaning that the second and any subsequent lines of an entry are indented to the right, sort of like a bibliography; “or with ordinary first-line paragraph indents,” meaning that each entry would be indented like any other paragraph in the main text
Also, use the same font size and selection in the glossary as in the main text.
Book glossary examples
Here are some more examples from actual book glossaries.
Glossary format
Let’s recap. Glossary formatting is as follows, with the information provided by The Copyeditor’s Handbook:
Term. In bold, followed by a period.
Definition(s). Initial capital letter and terminal period, colon, or dash. Sentence fragment followed by a period. Additional sentences if/as needed. Multiple definitions numbered (1), (2), and so on, each ending with a period.
Cross-reference indicator. If no definition is given, the indicator follows the term, with See, in italics. If a definition is given, See also [something]. Multiple references are separated by a semicolon. Cross references are followed by a period.
Use the same line spacing and font as in the main text. Blank lines between entries. Indent each entry like a paragraph in the main text, as you would a bibliography, or not at all.
Editing your glossary
According to The Copyeditor’s Handbook (as quoted on pp. 302, 303), this is what a professional copyeditor would do (but anyone can do these things):
edit or rewrite “any definitions that are significantly more or less detailed than the others”
“make sure that the terms, definitions, and cross-references are styled consistently”
“copyedit the spelling, capitalization, hyphenation, and punctuation of the definitions”
“correct definitions that are wordy, [redundant], or unclear”
“check every cross-reference to be sure the cross-referenced term appears in the glossary”
think of terms that “could be added to or deleted from the glossary” and proceed accordingly
do another “quick read-through to catch any overlooked errors”
Whether you’re writing a textbook, a nonfiction how-to book, or an epic fantasy novel, a glossary may be worth adding to your own writing. Now you know how to go about it!
More author resources:
buy a copy of The Chicago Manual of Style, 18th edition (2024)
buy a copy of The Copyeditor’s Handbook, 4th edition (2019)
Tips and best practices for other parts of the book, including the acknowledgments and the appendix.
Digital downloads, courses and coaching services for getting published.
—Daniel (US-based nonfiction book publishing coach and editor since 2017)