To serve as an administrator for or of.
A systems administrator (one who maintains a computer system or network).
A user of a discussion forum, website, etc. with privileges allowing them to control or restrict the activity of other users.
Administration, or administrative work.
An administration (a body that administers; the executive part of government).
An administrator (one who administers affairs).
To act as a flagship for.
The most important one out of a related group.
The ship occupied by the fleet's commander (usually an admiral); it denotes this by flying his flag.
The ship regarded as most important out of a group, e.g. a nation's navy or company's fleet.