Suppose we define an acronym in a scientific paper.

Should we do it like this?

(...) We call this approach the First Output Once (FOO) (...)

Or like this?

(...) We call this approach the first output once (FOO) (...)

  • 6
    Check with the journal. Some will have formal style guides. Otherwise, be consistent. The worst that will likely happen is that the copy editor will change your formatting. Oct 13, 2021 at 13:05
  • 12
    I really hope you don't have a BAR acronym in the same paper...
    – Jon Custer
    Oct 13, 2021 at 13:55
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    @RichardErickson: The last time a copy editor did something on acronyms in one of my papers, they insisted that I spell out CPU and RAM at first usage, so I wouldn’t rely too much on them.
    – Wrzlprmft
    Oct 13, 2021 at 17:44
  • 1
    @Wrzlprmft I've had journals require I spell out those term, but they were biology journals where a reader may not know those term. Also, it's a style question, which are often specific to the journal. Oct 13, 2021 at 19:44
  • 4
    As a side note, when mentioning a name, I would either quote or italicize: We call this approach "first output once" (FOO), to make it clear you are assigning a name. Some journals reserve italics for domain-specific things (i.e. foreign words, species names, etc) so I prefer quotes. Oct 13, 2021 at 20:22

4 Answers 4


It doesn't really matter. Pick the option you prefer, and then the important thing is to be consistent throughout the whole paper.


Capitalisation where you wouldn’t expect it orthographically is irritating and breaks the reading flow, so I would avoid it whenever possible.

Rarely, it can be helpful to clarify where your acronym comes from by typographically emphasising the respective letters, but capitalisation is no common emphasis (except for all caps, but that doesn’t work here). Rather I would use boldface. It is clearly emphasising without breaking any spelling rules or similar:

We call this approach first output once (FOO).

This has the advantage that it also works if your acronym contains lowercase letters, stands for proper names, other acronyms, and similar. For example:

We call this directed asynchronous Monte Carlo lesson (DAMoCLes)

(Note that I would opt for no emphasis at all in either example, but then they are obviously just examples.)

  • 10
    Well, yes, except the emphasis is unnecessary and distracting in the first example, and maybe even more so in the second. Just use lower case followed by the (capitalized as appropriate) acronym.
    – Bob Brown
    Oct 13, 2021 at 23:41
  • 1
    @BobBrown: Mind that the example from the question is clearly chosen to have an example, not because it’s the actual acronym the asker wants to introduce, but also see my edit.
    – Wrzlprmft
    Oct 14, 2021 at 13:21
  • 3
    If really necessary, I personally would prefer underscores to boldface, as it introduces a smaller change. But I would also simply provide the acronym without explanation (and if that is unintelligible, maybe it isn't a good acronym).
    – cheersmate
    Oct 14, 2021 at 13:38
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    Boldface where you wouldn’t expect it is irritating and breaks the reading flow, so I would avoid it whenever possible...
    – NotThatGuy
    Oct 14, 2021 at 14:41
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    @Wrzlprmft Boldface breaks reading flow for me much more than capitalisation does. Conservative use of continuous bold sections typically isn't a problem, but if there are short disjoint bold bits (as shown here), this causes my eyes to get stuck on those and it takes me like 10 times longer to read it. YMMV.
    – NotThatGuy
    Oct 14, 2021 at 18:33

As mentioned by others, there is no definitive rule (except if defined by the journal). However, let me give you a reason for and against capitalization.

On the one hand, capitalization makes it clearer and easier to see what the acronym stands for. Especially if the acronym is long or uses multiple letters from the same word, capitalization can be useful.

However, I have seen referees see capitalization as "condescending" to the reader, in the sense that it implies that the reader could not have figured out what the acronym stands for without it.


You capitalize the initial letters of a proper noun. There is no rule that you would capitalize letters merely because you want to make an initialism out of them. You may be getting confused because long proper nouns are often turned into initialisms. It is only proper nouns that are capitalized.

  • Agreed. Just because a phrase has an acronym, it doesn't excuse incorrect capitalization. Oct 14, 2021 at 21:58
  • Actually Breandán, Xerxes, both acronyms and initialisms very often do excuse "incorrect" capitalization. CAD and CAT scanning, MAD and MCP show where the traditional rule fails. NASA and NATO do get their capitals from their correct, full-out forms… but any number of modern journals think they're better off breaking both rules at the same time with eg, Nasa or Nato… Oct 15, 2021 at 0:29

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