coma

(noun) a state of deep and often prolonged unconsciousness; usually the result of disease or injury. Synonyms: comatoseness.

(noun) (botany) a usually terminal tuft of bracts (as in the pineapple) or tuft of hairs (especially on certain seeds).

(noun) (astronomy) the luminous cloud of particles surrounding the frozen nucleus of a comet; forms as the comet approaches the sun and is warmed.