An ace is known in some states and countries like the U.K. and is known as a 3.5-4 grams of weed. It has been mistaken as a weed ciggarette, which this is false for a Weed cig is a joint.
Johnny: Dude lets smoke this Ace(weed)
Jimmy: Sure, with what
Johnny: an ACE
Jimmy: You mean a joint dumbass