(n). A hat or any head covering that someone places on their head. Also relating to a condom for one's penis.
Bryan: Bro where'd you get that awesome dome cap?
Mike: The one with the lakers logo on it? It's dope huh?! I got it from the hat store down the street
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Mike: Bro be sure you put that dome cap on before you do your thing with that girl
Bryan: You're right, I don't want to be a daddy right now
Shot or otherwise damaged in the head.
Kurt Cobain dome capped himself with a shotgun.