coma
nounUK /ˈkəʊmə/
US /ˈkoʊmə/
A deep sleep that a person cannot wake up from.
After the accident, he was in a coma for three weeks.
OTHER MEANINGS
2. In astronomy, the cloud of gas and dust around the nucleus of a comet.
The comet's coma glowed brightly as it neared the sun.
3. In botany, a tuft of hair at the tip of a seed.
The coma helps the seed catch the wind and spread.
4. In optics, a blurring defect in a lens or mirror.
The telescope image showed coma near the edges.