A boy kept for unnatural purposes.

A man or boy who prefers to be sexually passive.

Zeus was so impressed with the beauty of the Trojan youth Ganymede that he took the form of an eagle and brought him to Olympus to become the cupbearer of the gods. The Latin rendering of Ganymede's name was Catamitus, and his relationship with Zeus (or Jupiter) was interpreted by some as overtly homosexual to lend divine authority to ancient pederastic practices; today a catamite is still the designation for a boy used for pederastic purposes.

a sexually abused young boy

A catamite was the younger partner in a pederastic relationship between two males in the ancient world, especially ancient Rome. The word is derived from the Latin catamitus, itself borrowed from the Etruscan catmite, a corruption of the Greek Ganymedes, the boy who was seduced by Zeus and became his beloved and cupbearer in Greek mythology.