Excellent, first class. Used extensively since the late 1950s in the USA, since the mid-1960s in Australia, and by the 1970s, especially by teenagers, in Brit- ain. The origin of the term is obviously in the highest value playing card, the meaning now having been extended from 'best' to 'smartest', 'cleverest', etc. an ace car That film was really ace. She's aces!