coma
A state of unconsciousness from which one may not wake up, usually induced by some form of trauma.
Other meanings
A cloud of dust surrounding the nucleus of a comet.
A defect characterized by diffuse, pear-shaped images that in an ideal image would appear as points.
Where this comes from
This definition is adapted from “coma” on Wiktionary, by its contributors, published under CC BY-SA 4.0. This page is published under the same licence.