Nouns

(n)coma, comatosenessa state of deep and often prolonged unconsciousness; usually the result of disease or injury
(n)coma(botany) a usually terminal tuft of bracts (as in the pineapple) or tuft of hairs (especially on certain seeds)
(n)coma(astronomy) the luminous cloud of particles surrounding the frozen nucleus of a comet; forms as the comet approaches the sun and is warmed