Many 'Latin' words in English have both Latin-style plurals and English-style plurals:

  • referendum – referendums, referenda.
  • minimum – minimums, minima.
  • gymnasium – gymnasiums, gymnasia.
  • aquarium – aquariums, aquaria.
  • amoeba – amoebas, amoebae.
  • antenna – antennas, antennae.
  • formula – formulas, formulae.
  • index – indexes, indices.
  • appendix – appendixes, appendices.

In technical language, generally, Latin-style is the only proper form of Latin plurals.

In all other contexts where both Latin-style and English-style are proper, which style of plural should I use?

  • 9
    Language, whether spoken or written, should be transparent. By this I mean that the listener or reader should not be distracted from focussing on the idea being communicated. If a grammatical construction no matter how "correct" is a distraction from the underlying message then, to paraphrase a phrase often misattributed to Churchill, it is a construction up with which I will not put.
    – user6925
    Commented Apr 4, 2011 at 23:54
  • 3
    @Alexander: and therefore your answer is...
    – nico
    Commented Apr 15, 2011 at 20:57
  • 2
    I claim we should promote the use of the Latin plural forms. When enough people adopt them, we'll drive the English-style plural forms into disuse. No more of these linguistic torture apparatuses! seseses!
    – einpoklum
    Commented Jan 25, 2014 at 18:35

7 Answers 7


In general, you can look to overall usage to get an idea of which to use. Searches of COHA, COCA, and the Google Books Ngram Viewer are great sources of data for that. However, one thing to consider is that for many of these words, I would personally use both of the plurals in different situations. So consider using a context search on COCA for perspective when doing research.

  • For example, I would speak of indices of economic decline, but of tracking major market indexes. Similarly, array indices but database indexes.

  • I would use minima in a mathematical context, but I would never speak of needing to carry cash because all the restaurants have $10 minima for using credit cards. I would speak of “$10 minimums

  • I would refer to a table of formulae in a math textbook but talk disparagingly of those looking for “magic formulas and shortcuts”.

  • A doctor who has performed many appendectomies I would say has removed many appendixes, but the last third of my calculus textbook consisted of nothing of appendices containing tables of integrals and values of trigonometric functions.

  • 5
    This answer perfectly captures the problem. There is no formula you can apply here. You have to develop a familiarity of what the normal usage is for a given context. "Curricula," for example, as a standard conversational plural is probably going to be surpassed by "curriculums" in the near future.
    – The Raven
    Commented Apr 28, 2011 at 21:20
  • 2
    @TheRaven: "There is no formula you can apply here." - But are there formulas or formulae? :P
    – V2Blast
    Commented Sep 11, 2020 at 0:26

A very short, preliminary answer: it depends on the noun. Some nouns should always take the Latin plural, some can take either, and others should always have the English plural. Even in academic writing, not all Latin forms would sounds proper. If I have time I will look up examples and edit them in.

  • 1
    Heh, this seems to agree closely with Jimi's answer. (The regional difference is important too.) As a student of science, I often find it a conundrum when to use Latin/English plurals, even being British! Maybe we should follow Isaac Newton and write all scientific papers in (Modern) Latin, hah. :)
    – Noldorin
    Commented Jan 17, 2011 at 1:12
  • 2
    @Noldorin: Thank you! If only! That would be marvellous. Commented Jan 17, 2011 at 1:36

As an actual classicist, I'd argue for the English plural in all but a few cases. Unless you are absolutely, completely sure you know the correct classical plural, or the classical plural is the normal plural, use the English plural. Using the classical plural may have a nice ring to it, but if you get it wrong it's so, so wrong.

  • 3
    Absolutely right, you should be completely sure before even considering the Latin plural, see "octopus". That said, as another classicist, I try to squeeze in Latin plurals whenever they are not totally ridiculous. I think it might even be seen as "cute geekiness" if a classicist crosses that line. Commented Jan 17, 2011 at 21:56
  • You should also be aware of unusual modern usages, e.g. although referenda is the appropriate plural of referendum in Latin, referendums is the preferable plural in English since a referenda is a plebiscite on a number of issues (whereas a referendum might be on only a single issue).
    – gpr
    Commented Jan 21, 2011 at 13:20
  • 3
    @gpr -- I've never heard "a referenda" and my dictionary doesn't back you up. Do you have a cite? @arnholt -- how do you expect people to get it right without practice ? Commented Apr 15, 2011 at 2:00
  • @Malvolio - rather annoyingly, the online Oxford doesn't back me up either, although this Wikipedia article quotes from it: en.wikipedia.org/wiki/Referendum#Terminology. Maybe it's only used by classicists, pedants, and psephologists :(
    – gpr
    Commented Apr 16, 2011 at 22:52
  • 1
    Well, if people start using the right plurals then eventually nobody will get it wrong because they'll know for certain what the right form is.
    – einpoklum
    Commented Jan 25, 2014 at 18:32

Most generally, American speakers tend to use the English-style plural, while British (and related) speakers favor the Latin-style. Of course, there are those words whose Latin-style plural forms are non-negotiable on either side of the pond, such as bacteria and criteria. And there are also those whose English-style plurals are universally preferred, e.g. moratoriums, apexes, etc.


As Cerberus said, usage differs between nouns. Unfortunately, there are no simple rules that are completely effective at predicting which nouns tend to take which kind of plurals.

The use of one kind of plural versus the other also may depend on context, but the way you've put it is not quite accurate ("In technical language, generally, Latin-style is the only proper form of Latin plurals"). There are many situations in technical language where English-style plurals are correct.

Some notes on specific nouns or categories of nouns:

  • For crisis and axis, people rarely use regularly formed English-style plurals ending in -sises/-xises. You'll almost always see crises and axes instead. Other nouns derived from Greek that end in unstressed -sis also tend to use the Latin-style plural in -ses to the exclusion of the English-style plural, such as basis, thesis, hypothesis, neurosis.

  • Nouns ending in -or have plurals ending in -ors in English, not in -ores as in Latin. Thus, we say and write professors, vectors, operators, sectors, etc. (These nouns have various origins; not all English nouns ending in -or are words in Latin.)

  • Latin-style plurals are extremely rare for the following nouns (this is not a comprehensive list): simile, rationale, specimen, omen, regimen, ratio.

As mentioned in Andreas Blass's answer, some words, such as antenna, allegedly are or should be used with different plurals for different senses.


Per Cerberus:

"Some nouns should always take the Latin plural, some can take either, and others should always have the English plural."

Give him a +1 for that - it's correct. There is no rule that applies to all Latinates; in usage they are case-by-case. "Agenda" is plural but you never see "agendum." "Symposia" is the plural but "symposiums" is far more common. These are all moving targets, largely depending on frequency of use and location or agency of that usage.

This is one of the most difficult areas of English because a sensitivity to "the usual thing" in any given context is critical to striking the right note.

  • 2
    I've never seen symposiums, probably because the kind of people who go to symposia are the kind of people who like Latin plurals (i.e., my kind of people). Commented Apr 15, 2011 at 1:58
  • Perhaps it depends on the extent to which the word has become absorbed into English, if a loan word from any other language (not just Latin) is absorbed thoroughly it becomes an English word and then has an English plural unless the foreign plural is adopted as well. Sometimes a plural is adopted and then used as a singular noun, for example "The data is available".
    – BoldBen
    Commented Jul 2, 2019 at 9:06

On the basis of what I've heard people (in the Midwest of the U.S.) say, I have the impression that:

  1. Mathematicians say "formulas" but philosophers say "formulae".
  2. Buildings and television sets used to have antennas atop them (before cable became common), but insects and little green Martians have antennae.
  3. It is indeed dangerous to form "classical" plurals carelessly; I've heard a university professor use "quora" as the plural of "quorum".

Not the answer you're looking for? Browse other questions tagged or ask your own question.