Inf. Good-bye. (Sometimes the reply is After while(, crocodile.)) Bob: See you later, alligator. Jane: After while, crocodile. Bob: Bye, Tom. Tom: See you later, alligator. Bob: Later.
interj. Good-bye. (From the 1930s. Answered with After while, crocodile.) TOM: Bye. BILL: See you later, alligator. BILL: See you later, alligator. TOM: After while, crocodile.
Bye! The title of a 1950s rock-'n'-roll smash hit by Bill Haley and His Comets, the phrase was already in use, especially in the South. For a decade or more, hep/hip/with-it cats and chicks ended conversations with the phrase. The standard reply was the song's next line: “after a while, crocodile.”