Minotaur

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Greek Mythology A monster who was half man and half bull, to whom young Athenian men and women were sacrificed in the Cretan labyrinth until Theseus killed him.

Century Dictionary and Cyclopedia

1. n. In Greek myth, a monster represented as having a human body and the head of a bull, who was the offspring of Pasiphaë, wife of Minos, and a bull sent by Poseidon. He was confined in the Cretan labyrinth and fed with human flesh, devoured the seven youths and seven maidens whom Minos compelled the Athenians to send him periodically as tribute, and was killed by the hero Theseus, a member of the last company so sent, who escaped from the labyrinth by the aid of Ariadne, daughter of Minos. Hence, in modern literature, the name is used to characterize any devouring or destroying agency of which the action is in some way comparable to that attributed to the Cretan monster.

Wiktionary

1. n. A fictional creature, half man and half bull.
2. n. Greek mythology, with "the" A minotaur, half man and half bull, who dwelled in the labyrinth in Crete and who was killed by Theseus.

GNU Webster's 1913

1. n. (Class. Myth.) A fabled monster, half man and half bull, confined in the labyrinth constructed by Dædalus in Crete.

WordNet 3.0

1. n. (Greek mythology) a mythical monster with the head of a bull and the body of a man; slain by Theseus