membership
/ˈmembəʃɪp/noun
mass noun
1- the fact of being a member of a group会员身份（或资格、地位）：
countries seeking membership of the European Union
谋求欧盟会员国资格的国家
as modifier a membership card.会员证。
1.1
- in sing. the number or body of members in a group会员数; 全体会员：
our membership has grown by 600,000 in the past 18 months.
在过去18个月里, 我们的会员增加了600,000个。