A state of unconsciousness from which one may not wake up, usually induced by some form of trauma.

(astronomy) A cloud of dust surrounding the nucleus of a comet. / (optics) A defect characterized by diffuse, pear-shaped images that in an ideal image would appear as points.

plural of coma

plural of coma (“cometary nuclear dust cloud”) / plural of coma (“cometary dust cloud, etc”)

Any coma that results from a greater than normal amount of glucose in the blood

(astronomy) A small dim summer constellation of the northern sky, said to represent an offering of hair from Queen Berenice II of Egypt. Originally considered to represent the tuft of hair on the end of Leo's tail.

(medicine) A state in which the patient lies with eyes open, yet unresponsive to the outside world.

Alternative spelling of coma vigil

(informal, humorous) A state of lethargy and sleepiness that comes on shortly after eating a large or heavy meal.

(slang) The collapse of a dot-com or of the dot-com bubble.