1. (

• coma ,
• comatoseness

) a state of deep and often prolonged unconsciousness; usually the result of disease or injury ;

2. (

• coma

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

3. (

• coma

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