We use indefinite pronouns to refer to people, things or places without saying exactly who or what they are.
Compare:
anybody |
anything |
anywhere |
everybody |
everything |
everywhere |
nobody |
nothing |
nowhere |
somebody |
something |
somewhere |
Note:
anyone = anybody
everyone = everybody
no one = nobody
someone = somebody
No one is written as two words, or with a hyphen: no-one.
When an indefinite pronoun is the subject it is followed by a singular verb.
Indefinite pronouns are singular, but to refer back to them we use plural pronouns, e.g. they, their, themselves, etc.