I've always just said friend for friend and girlfriend.
Does it really matter what gender they are?
Maybe I'm being callous here.
well no, if you want to call killa your girlfriend thats between you and him.
it doesnt matter what gender they are - but what im sayin is that your bestfriend (if its a guy) is your boy friend.
sounds weird
but if you have a bestfriend thats a girl that is your girl friend but not your girlfriend (romantic).
but society translates girlfriend and girl friend as the same thing.