a) A safehouse.
b) A place where a stash of drugs or money is kept (usually a girl's house) in order to avoid having it stolen or busted.
c) A place that can be easily accessed at any time and few know about.
d) Sometimes a place to do deals but not frequently to avoid making it "hot".
e) Not to be confused with a crib because a real trapstar doesn't want his house to have much "stuff" in it because it will become a target for theives, haters, police. (In fact, a trapper doesn't really even want people to know where his crib or his trap(s) are.)
"I gotta stop by the trap real quick to weigh out this "cuttie" for dude."
"You need two O's? Okay I got them at the trap, I'll be right back."