3. To be in service; to do duty; to discharge the requirements of an office or employment. Specifically, to
act in the public service, as a soldier, seaman. etc.
Many . . . who had before been great commanders, but now served as private gentlemen without pay.
Knolles. 4. To be of use; to answer a purpose; to suffice; to suit; to be convenient or favorable.
This little brand will serve to light your fire.
Dryden.
As occasion serves, this noble queen
And prince shall follow with a fresh supply.
Shak. 5. (Tennis) To lead off in delivering the ball.