Coma

Part of speech: noun

Pronunciation: /ˈkəʊmə/

Definitions

1. A profound state of unresponsiveness resulting from severe injury or illness combined with the outer gas layer surrounding the nucleus of a comet
2. An extreme state of unconsciousness where a person cannot be awakened ; the nebulous envelope of gas and dust that surrounds the nucleus of a comet as it approaches the sun
3. A deep medical condition marked by unresponsiveness to stimuli ; the glowing cloud of gas released from a comet's nucleus forming a fuzzy outer layer

Etymology: The word has two unrelated lives that happen to share a spelling. The medical sense comes from Ancient Greek "kôma", meaning "deep sleep", which English took directly as a learned borrowing. The astronomical and botanical senses come from a different Greek word, "kómē", meaning "hair of the head", which passed into Latin as "coma" and was later borrowed into English. So a sleeper in a coma and a comet with its glowing halo are, etymologically, a sleep and a head of hair. The hair meaning is the one that stretched furthest. Ancient writers used "kómē" for the tuft on a helmet or the foliage of a tree, and the same idea of a loose, fluffy mass carried over to the cloud around a comet's nucleus. Botanists later applied it to the tuft of silky hairs on milkweed seeds and to the bracts of certain plants, and the sense of a soft, bushy spread of foliage followed the same line.

Synonyms: unconsciousness, stupor, suspension

Antonyms: alertness, consciousness