I am teaching myself Latin. Right now I study how to make plural of nouns. I have found some rules online, depending on the ending of a noun in a nominative singular form. The website says that most times there are two versions of the plural. Is it like that? For example, an apple "malum", can I use both "mala" and "malums"?

(I have found only "mala" in a dictionary for apples in Latin.)

Thank you.

EDIT: Here is an illustration of the two options of a plural form rule:

@-a, plural -s or -ae

formula, formulas or formulae

@-ex, plural -exes or -ices

index, indexes or indices

@-eau, plural -eaus or -eaux

bureau, bureaus or bureaux


@-us, plural -uses or -i

focus, foci or focuses

locus, loci [no: locuses]

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    Pretty sure bureaux isn't Latin! Commented Dec 17, 2021 at 20:09
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    You will find the correct forms on Wiktionary, it is generally very reliable. But the real answer is: Forget about dictionaries, buy a beginner's textbook or grammar and start learning about declensions. Latin has five or so of them (the exact counting depends on your textbook), and once you know them, you won't need a table for every single word (and the best dictionaries don't have such tables). Commented Dec 17, 2021 at 20:43
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    My favorite is "malum, A declension, masculine gender." At this point I wonder if the site is a troll site deliberately set up to lead people astray.
    – cmw
    Commented Dec 17, 2021 at 20:54
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    @Jan Wiktionary is right and you are wrong. Indexes may happen in English but not in Latin. Commented Dec 17, 2021 at 21:04
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    @Jan In Latin, the only nominative plural for formula is formulae. The accusative plural is formulas. Wiktionary does mention both.
    – cmw
    Commented Dec 18, 2021 at 14:12

2 Answers 2


I'm afraid the website you're looking at isn't about Latin—these are rules for pluralizing Latin loanwords in English. In English, for example, the plural of "index" can be either the English-derived "indexes" or the Latin-derived "indices". But in Latin, the only valid plural is indicēs.

While it does have the occasional error or overgeneralization, Wiktionary is generally quite good at Latin declension. You might find it a more useful tool for looking up words. But whatever textbook you're learning from should also provide all this information in a useful way. If it doesn't, you should find a better textbook!


No, only mala is correct. Malums is not a possible Latin form.

What website are you using? It seems not to be particularly reliable.

  • Thank you. But how do I know in general? Please have a look at the initial post. Is there a reliable dictionary?
    – Jan
    Commented Dec 17, 2021 at 20:07
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    Very likely an English dictionary that allows Latin and English forms for Latin loanwords. Commented Dec 17, 2021 at 20:08
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    @Jan There sure are several: latin.stackexchange.com/questions/867/… Commented Dec 17, 2021 at 20:12
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    Thank you for the link Sebastian.
    – Jan
    Commented Dec 17, 2021 at 20:28

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