When using the acronym package, how can you correctly pluralize an acronym which ends on 'S'?

Take the acronym: OS - operating system

It should be pluralized as OS's, but is pluralized as OSs when using \acp.

  • 3
    Note that while OS's is an acceptable plural, it's not the only right answer -- check your style guide if one applies (CMOS and NYT say yes, APA says no, the Guardian implies no by example). English.stackexchange discussion (not the first, probably not the last).
    – Chris H
    Oct 5, 2015 at 16:22
  • 1
    Echoing @ChrisH but note OP's (apostrophe indicating possession there) link - english.stackexchange.com/a/58994/92427 gives specific mention of OS
    – beldaz
    Feb 5, 2018 at 2:05

2 Answers 2


To define plural exceptions, you can use \acrodefplural:


\acrodefplural{OS}[OS's]{Operating Systems}



\acro{OS}{Operating System}


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More information can be found on Section 2.3.1 Non standard and foreign plural forms of the acronym package documentation (see here).

  • 2
    It's so difficult to google for this stuff. I remember googling for "latex acronym plural exception" and nothing interesting showed up. Perhaps it's just a matter of knowing where to look, and TeX is a great help! Thanks. Dec 17, 2011 at 20:16
  • 5
    @StevenJeuris: You're welcome! Now, thanks to your question, if I google for "latex acronym plural exception", this question appears in the second place, so now other users will find a quick solution ;-) Dec 17, 2011 at 20:20
  • 2
    When I use this solution the usages of the plural form of that acronym no longer gives a link to the acronym list. Why is that? Can it be solved?
    – Kajsa
    Jul 28, 2015 at 9:47
  • 2
    I have the same questions as @Kajsa.
    – JCML
    May 19, 2016 at 17:11
  • I have the same questions as @JCML
    – ploth
    May 3, 2019 at 11:13

To also have the plural show up as a link to the acronym list, enter two acronym entries similar to as such:

\acro{TSE}{transmissible spongiform encephalopathy}
\acrodefplural{TSE}{transmissible spongiform encephalopathies}

Then make sure you reference the acronym in the text body as such:


This will now enter in the text with a link to the acronyms list as such:

"... transmissible spongiform encephalopathies (TSEs) ..."

  • Welcome to TeX - LaTeX! Isn't this the same solution as in @Gonzalo's answer (just using a different acronym)?
    – cgnieder
    Oct 5, 2015 at 14:25
  • no @Gonzalos answer gives no hyperlink
    – Leon D
    Oct 22, 2020 at 12:48
  • When I use \acrodefplural I cannot see the acronym in the list of acronyms and it does not make the hyperref link to it. Dec 29, 2020 at 10:43

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