One Monster, and a Word That Outgrew It

The chimera is a single Greek monster with a fixed genealogy, not a general term for a hybrid. Homer describes it in the Iliad as lion in front, serpent behind and goat in the middle, breathing fire and of divine stock; Hesiod in the Theogony makes it a child of Typhon and Echidna and gives it three heads. Its one story is its death: the hero Bellerophon, mounted on Pegasus, kills it from the air, in some versions by dropping a lump of lead down its throat that the fire melts.

The Lycian setting is often connected to a real place, Mount Chimaera near Olympos, where natural gas vents burn perpetually on the hillside. The modern senses of the word are metaphorical descendants: a "chimera" for an impossible fancy, and in biology a chimera for an organism of genetically distinct cells, both drawn from the idea of incompatible parts joined in one body, and both far from the specific fire-breathing beast of the Greek text.