I know that this a math question, but as it is really a very basic math concept I think any English user would know it, and it must be more related to English than knowing the math.

We call a number that is greater than 1 and is only divisible by 1 and itself, a prime number. What is a non-prime number greater than 1 called?

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    Since composite was indeed the word you were searching for, I suggest clarifying your question by asking what is a non-prime number larger than 1 called. It may not seem important, but it's best to be explicit, especially when crossing language barriers. (One would think that mathematical definitions do not vary by language, but they do. For example, 0 is considered positive in French.)
    – Dennis
    Commented Aug 26, 2018 at 14:09
  • only divisible by one and itself
    – TimR
    Commented Aug 26, 2018 at 21:03
  • (...to be slightly pedantic you mean "integer" not "number". Prime/compositeness does not apply to e.g. 2.4 )
    – smci
    Commented Aug 27, 2018 at 3:12
  • @Dennis my understanding is that 0 is both positive and negative in French, ie the sets of both positive and negative numbers include 0. 'Strictly positive' refers to numbers greater than 0 and 'strictly negative' for numbers less than 0 there.
    – mcalex
    Commented Aug 27, 2018 at 5:22

3 Answers 3


From Wikipedia:

Composite (number)
A composite number is a positive integer that can be formed by multiplying together two smaller positive integers. Equivalently, it is a positive integer that has at least one divisor other than 1 and itself. Every positive integer is composite, prime, or the unit 1, so the composite numbers are exactly the numbers that are not prime and not a unit.

It's not a math question. It's a question about a word. No different than if you asked, as in another question I read today, what legislation and autonomy are. Those are words about concepts in law or political science. But asking about their meanings isn't a question of law or political science.

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    Note that 1 is neither prime nor composite, so composite doesn't quite mean non-prime.
    – Dennis
    Commented Aug 26, 2018 at 13:49
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    That really is getting too mathy. Prime and composite most often refer to whole numbers. But they can be applied, really mathy, to other classes of numbers. I've never heard of them being applied to irrational numbers. But complex numbers, yes. I'm pretty sure this is not what's being asked. I think it's safe to say that Composite is the correct answer here. Commented Aug 26, 2018 at 13:54
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    @Dennis I know that I have a BS in pure math. I only didn't know what it is called in English Commented Aug 26, 2018 at 13:57
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    @Dennis the OP's definition " a number that is only divisible to 1 and its own" makes 1 a prime number. Not everyone would agree with that, but it's the OP's question, not mine or yours - and you already said "mathematical definitions vary by language" ;)
    – alephzero
    Commented Aug 26, 2018 at 15:08
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    math.stackexchange.com would have been a good place to post this. This is a question about the terminology of a certain field of study. Where there's a site devoted to answering questions about such a field. that's where questions about the jargon of the field belong. Questions about terminology do appear there. Commented Aug 26, 2018 at 21:46


(mathematics) Capable of being factored. For integers synonyms are composite, non-prime.

  • that's a good answer - I think "composite" is more common, though.
    – Fattie
    Commented Aug 27, 2018 at 6:28

The technical term is "composite number" or "composite." This generalizes to other than natural numbers (Gaussian Integers, Finite Fields, etc.) by classifying numbers into "print," "composite," or "units."

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