The term 'The Hairy APE' is a 1922 play by Eugene O'Neill. It follows the story of a brutish, uneducated laborer named Yank who works in the boiler room of an ocean liner. Yank's search for identity and purpose leads him to a zoo, where he is confronted with his own animalistic nature. The play is a commentary on the alienation of the working class and the dehumanizing effects of industrialization. The crossword solution for this term is 'APE', which is a three-letter word.