If process is a process object it must be the result of a call to start-up-server.
server-terminate terminates it, and frees all the associated resources.
If process is
nil or is not supplied, the call to
server-terminate must be inside the scope of the process that was created by start-up-server, which can by either function or announce that you passed to start-up-server.
t in this case, and the actual termination happens after your function (that is, function or announce) returns.
t if the server was still active when it was called, otherwise it returns
nil. It can be called repeatedly on the same server, and can be used as a predicate to check whether the server really went away.
In LispWorks 6.0 and earlier versions, process-kill is the way to terminate servers. This is deprecated, because it may leave some value in an invalid state.
LispWorks User Guide and Reference Manual - 20 Sep 2017