Trephan

Part of speech: noun, verb

Definitions

1. A small circular surgical saw used to cut out a round piece of bone ; to operate on the skull by removing such a disk of bone
2. A hollow cylindrical bone saw surgeons use to cut a round section from the skull ; to perform surgery that removes a circular piece of bone
3. An instrument with a toothed circular blade for boring into bone ; the act of using that instrument to take a round disk out of the skull

Etymology: Ancient Greek surgeons used "trypanon," a word meaning "borer" or "auger," from the verb "trypan," "to bore." The Romans borrowed it as "trypanum," and it passed into Old French as "trepan." English took the word for a surgical saw that cut a disc from the skull, usually to relieve pressure after a head injury. The noun and the verb both come from that instrument. To trephan is to perform the operation, so the act is named after the tool that carried it out. The same Greek root gives us "trypanosome," the name for a parasitic microbe whose corkscrew-shaped body was thought to resemble a borer.

Synonyms: trephine