Meaning of “membership” - Learner’s Dictionary

membership

noun uk us /ˈmembəʃɪp/
BELONGING [ C, U ]

B1 the state of belonging to a group or an organization:

I've applied for membership of the union.
a membership card/fee
PEOPLE [ group ]

the people who belong to a group or an organization:

Union membership is now over three million and rising.

(Definition of “membership” from the Cambridge Learner’s Dictionary © Cambridge University Press)