A client asked me, “Should a Latin expression be hyphenated when I use it as an adjective? For example, should status quo be hyphenated?”
No. In general, there’s no need to hyphenate Latin phrases used in English. To know when to hyphenate and when not to hyphenate Latin words used in English, you need to first understand hyphenation rules.
The purpose of hyphenation
Most compound, or multi-word, adjectives placed directly before a noun they modify need a hyphen, for clarity. For example, if you write third party expert, the reader won’t know if you’re talking about the third expert in parties or an external consultant.
The humble hyphen has the power to wash away the ambiguity: a reader cannot misinterpret third-party expert.
So, the purpose of using a hyphen is to clarify the meaning of a word or phrase.
Examples of Latin phrases used as adjectives
Here are the most commonly used Latin phrases I’ve seen when editing journal articles:
- a posteriori (a posteriori error estimation)
- a priori (a priori information)
- ad hoc (ad hoc network)
- ad hominem (ad hominem attack)
- ad interim (ad interim results)
- ad valorem (ad valorem tax)
- bona fide (bona fide treatment)
- de facto (de facto border)
- exempli gratia (e.g.)
- ex gratia (ex gratia assistance)
- ex post facto (ex post facto design)
- et alia (et al.)
- id est (i.e.)
- in situ (in situ rock stress)
- in vitro (in vitro evaluation)
- in vivo (in vivo experiment)
- per capita (per capita income)
- per diem (per diem cost)
- status quo (status quo bias)
- viva voce (viva voce examination)
To hyphenate or not to hyphenate Latin?
When Latin phrases modify a noun, the resulting expression is unambiguous. For example, you cannot misread in vivo experiment or per capita income. Both in vivo experiment and in-vivo experiment mean the same thing. And per capita income is the same as per-capita income.
So, there is no need to hyphenate Latin phrases such as these, because their meaning is clear even without a hyphen.
However, in some scholarly articles, you’ll find hyphenated Latin expressions. Two examples are ex-post-facto research design and status-quo bias. It’s not incorrect to hyphenate Latin phrases, but it’s often unnecessary, so when I edit academic articles for clients, I recommend deleting the hyphen in Latin phrases.
What do style guides say?
Most style manuals recommend not hyphenating foreign phrases (including Latin) used as adjectives. Here are just three examples:
The Chicago Manual of Style (CMOS)
According to this reference book for editors, foreign phrases should be “open unless hyphens appear in the original language”. So, if you follow The Chicago Manual of Style, do not add a hyphen to Latin expressions.
However, some Latin words are no longer foreign. You will find them in any good English dictionary. For these words, the regular hyphenation rules in English apply.
Publication Manual of the American Psychological Association (APA)
“Do not hyphenate foreign phrases used as adjectives or adverbs”. But APA gives an exception: ad-lib is hyphenated.
Again, it could be argued that some Latin phrases have been incorporated by the English language—you will find them in the dictionary. For some of these, you may want to use a hyphen for clarity. But, in general, there is no need to hyphenate common Latin expressions used in English (such as those in the bulleted list above).
New Oxford Style Manual
“Do not hyphenate italic foreign phrases unless they are hyphenated in the original language.”
The New Oxford Style Manual is coherent with the other two style guides on this list, recommending omitting the hyphen in Latin phrases.
CMOS, APA, and New Oxford Style Manual are just three of the major style guides I use as a freelance editor. I haven’t found a popular style guide that recommends using hyphens in Latin phrases. If you find one, please let me know and I’ll mention it in this post.
Advice on hyphenating Latin phrases
Whoever will review your manuscript may or may not expect you to hyphenate Latin expressions used as adjectives. So, when proofreading your work, follow your publisher’s style guide or manuscript preparation instructions.
If your publisher’s guidelines say nothing about hyphenating Latin expressions, the better option is to omit the hyphen. A hyphen can change the meaning of a phrase (as in fish eating bird vs. fish-eating birds). But that is rarely the case with Latin expressions.
If your publisher doesn’t have a specific style guide, or you will self-publish, do whatever you think works best for you. More important than whether you decide to hyphenate Latin phrases used as adjectives is to ensure your writing is clear and your punctuation choice consistent across the document.
Summary: Most Latin expressions don’t need a hyphen
In general, when you write in English, Latin phrases used as adjectives are not hyphenated. However, exceptions exist (such as ad-lib in APA Style), so check the style guide you need to use. If in doubt, leave out the hyphen. It has a lot of work to do in places where it’s indispensable.
Do you need a freelance editor for an academic paper? Send me a message at editor@languageediting.com.
Related posts:
- It’s a maze: Punctuation with quotation marks
- Why your grammar checker can’t make documents perfect
- Is “et al.” singular or plural?
Last revised on 19 June 2022
