noun

1. Gr. Myth. a fire-breathing monster, usually represented as having a lion's head, a goat's body, and a serpent's tail
2. any similar fabulous monster
3. an impossible or foolish fancy
4. Biol. an organism having two or more genetically distinct types of cells due to mutation, grafting, etc.

Etymology: ME & OFr < L chimaera < Gr chimaira, fabulous monster, orig., she-goat that has passed one winter < cheima, winter: see hibernate