- a state of deep, prolonged unconsciousness caused by injury or disease
- a condition of stupor or lethargy
Origin of comaModern Latin ; from Classical Greek k?ma (gen. k?matos), deep sleep ; from Indo-European base an unverified form keme-, to grow tired from source Sanskrit ?am?t?, to work, prepare, Classical Greek kamatos, fatigue, effort
- Astron. a comet's gaseous cloud surrounding the solid nucleus and forming, with the nucleus, the comet's head
- a bunch of branches, as on the top of some palm trees
- a terminal cluster of bracts on a flowering stem, as in pineapples
- a tuft of hairs at the end of certain seeds
- Photog. a blur caused by the spherical aberration of oblique rays of light passing through a lens
Origin of comaL, hair of the head, foliage ; from Classical Greek kom?, hair
Origin of comaGreek kōma, deep sleep.
- Astronomy The nebulous luminescent cloud surrounding the nucleus of a comet and composed of material evaporated from the nucleus when the comet is near the perihelion of its orbit. The nucleus and coma together form the head of a comet.
- Botany A usually terminal tuft or cluster, especially a tuft of hairs on a seed, as on a willow or milkweed seed.
- Physics A diffuse, comet-shaped image of a point source of light or radiation caused by aberration in an optical system.
Origin of comaLatin, hair, from Greek komē.
From Ancient Greek κῶμα (kōma, “deep sleep”).
- (astronomy) A cloud of dust surrounding the nucleus of a comet.
- (optics) A defect characterized by diffuse, pear-shaped images that should be points.
- (botany) A tuft or bunch, such as the assemblage of branches forming the head of a tree, a cluster of bracts when empty and terminating the inflorescence of a plant, or a tuft of long hairs on certain seeds.
From Latin coma (“hair of the head”), from Ancient Greek κόμη (komē, “hair”).