To come into existence.
To be in the first stage of some situation
To start, to initiate or take the first step into something.
Beginning; start.
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.