The term 'A Marx' refers to the four Marx Brothers, Harpo, Karl, CHICO, and Zeppo. Harpo was the mute brother who played the harp and was known for his slapstick humor. Karl was the eldest brother and the leader of the group, known for his wit and intelligence. CHICO was the middle brother and was known for his piano playing and comedic timing. Zeppo was the youngest brother and was known for his straight man roles. Together, the four Marx Brothers were a popular comedy act in the early 20th century.