Definition of “or” - Learner’s Dictionary

or

conjunction us uk strong /ɔːr/ weak /ər/
BETWEEN POSSIBILITIES

A1 used between possibilities, or before the last in a list of possibilities:

Would you like toast or cereal?
Is that a boy or a girl?
You can have beer, wine, or mineral water.
The house will take two or three years to complete.

More examples

CHANGE

B2 used to change or correct something you have said:

We told the truth, or most of it.
REASON

used to give a reason for something you have said:

She must love him or she wouldn't have stayed with him all these years.
NOT EITHER

A2 used after a negative verb between a list of things to mean not any of those things or people:

Tim doesn't eat meat or fish.
She doesn't have a telephone or a fax machine.

(Definition of “or” from the Cambridge Learner's Dictionary © Cambridge University Press)