coma (n.2) Look up coma at Dictionary.com
"head of a comet," 1765, from Latin coma, from Greek kome "hair of the head," which is of unknown origin. Earlier in English as a botanical term for a tuft of hairs (1660s).
coma (n.1) Look up coma at Dictionary.com
state of prolonged unconsciousness, 1640s, from Latinized form of Greek koma (genitive komatos) "deep sleep," which is of uncertain origin. A term for "coma" in Middle English was false sleep (late 14c.).