Member
From ACT Wiki
1. Pensions.
A beneficiary under an occupational pension scheme.
Pension scheme members may be:
i. Active (still accruing benefits by virtue of current service); or
ii. Deferred (no longer accruing benefits through having left the scheme, but entitled to receive benefits in the future); or
iii. Pensioners (currently receiving benefits). This third category will also usually include widows and other dependants of former members.
2. Company law.
In relation to a company, a shareholder.
3. Mutual organisations.
A retail customer of a mutual organisation, such as a building society.
4.
More generally, a participant in a closed group of some kind.
For example, a member-administered closed user group (MA-CUG).