# How to pluralize an acronym which ends in 'S' correctly?

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.

• 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). Oct 5, 2015 at 16:22
• Echoing @ChrisH but note OP's (apostrophe indicating possession there) link - english.stackexchange.com/a/58994/92427 gives specific mention of OS Feb 5, 2018 at 2:05

To define plural exceptions, you can use \acrodefplural:

\documentclass{article}
\usepackage{acronym}

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

\begin{document}

\acp{OS}

\begin{acronym}
\acro{OS}{Operating System}
\end{acronym}

\end{document}


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

• 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
• @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
• 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? Jul 28, 2015 at 9:47
• I have the same questions as @Kajsa.
– JCML
May 19, 2016 at 17:11
• I have the same questions as @JCML 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:

\acp{TSE}


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)? Oct 5, 2015 at 14:25
• no @Gonzalos answer gives no hyperlink 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