In particular in scientific writing, copulae using

to becan not only be used to describe the properties of something but also to recapture a definition, to define something or to indicate complete identity. For example, the first of the following sentences gives the definition of a prime number, the second one just describes its properties:A prime number is a natural number with exactly two divisors.

A prime number is a natural number.

Usually, it is clear from context how a copula is meant to be read, but now I am facing a case where it isn‘t. More specifically, I want a copula or syntactically similar construct to be clearly understood as describing only properties. I am thus looking for verbs or phrases meaning

to have the property of beingor similar (but less convoluted), i.e.:A prime number has the property of being a natural number.

I searched thesauri (1, 2) for synonyms of to be and found no satisfying answer as only other meanings of

to be,such asto exist,were covered.I am aware, that as a last resort I can completely rephrase the sentence, e.g.:

Prime numbers are a subset of the natural numbers.

Finally note, that the above are only examples (my actual problem is more complicated and requires background knowledge), so I am not looking for answers specific to this.

**Answer**

A prime number is a natural number.

That statement is ambiguous because it could potentially apply to just one prime or a set of primes that you happen to be discussing.

The easiest transformation is:

*Prime numbers are natural numbers.*

You can make this even clearer by saying:

*All prime numbers are natural numbers.*

but, in grammatical terms, that is unnecessary as the two statements are equivalent.

**Attribution***Source : Link , Question Author : Wrzlprmft , Answer Author : chasly – supports Monica*