The crossword solution for the term 'Who's On First?' is 'Straight Man' and the answer to the clue 'ABBOTT' is 6 letters. This is a reference to the classic comedy routine by Bud ABBOTT and Lou Costello, which was first performed in the 1930s. The routine is about a conversation between two men, with ABBOTT playing the straight man and Costello playing the confused one. The routine is still popular today and is often used as a metaphor for confusion or misunderstanding.