coma

¹ American  

[koh-muh] / ˈkoʊ mə /

noun

comas plural

1. a state of prolonged unconsciousness, including a lack of response to stimuli, from which it is impossible to rouse a person.

---

coma ² American  

[koh-muh] / ˈkoʊ mə /

noun

comae plural

1. Astronomy. the nebulous envelope around the nucleus of a comet.

2. Optics. a monochromatic aberration of a lens or other optical system in which the image from a point source cannot be brought into focus, the image of a point having the shape of a comet.

3. Botany.

   1. a tuft of silky hairs at the end of a seed.

   2. the leafy crown of a tree; cluster of leaves at the end of a stem.

   3. a terminal cluster of bracts, as in the pineapple.

---

coma ¹ British  

/ ˈkəʊmə /

noun

1. astronomy the luminous cloud surrounding the frozen solid nucleus in the head of a comet, formed by vaporization of part of the nucleus when the comet is close to the sun

2. botany

   1. a tuft of hairs attached to the seed coat of some seeds

   2. the terminal crown of leaves of palms and moss stems

3. optics a type of lens defect characterized by the formation of a diffuse pear-shaped image from a point object

---

coma ² British  

/ ˈkəʊmə /

noun

1. a state of unconsciousness from which a person cannot be aroused, caused by injury to the head, rupture of cerebral blood vessels, narcotics, poisons, etc

---

coma ¹ Scientific  

/ kō′mə /

comae plural

1. Astronomy The brightly shining cloud of gas that encircles the nucleus and makes up the major portion of the head of a comet near the Sun. As a comet moves along its orbit away from the Sun, the gas and dust of the coma dissipate, leaving only the nucleus. A coma can have a diameter of up to 100,000 km (62,000 mi.).

2. Astronomy See more at comet

3. Physics A diffuse, comet-shaped image of a point source of light or radiation caused by aberration in a lens or mirror. The image appears progressively elongated with distance from the center of the field of view.

---

coma ² Scientific  

/ kō′mə /

comas plural

1. A state of deep unconsciousness, usually resulting from brain trauma or metabolic disease, in which an individual is incapable of sensing or responding to external stimuli.

---

coma Cultural  

1. An abnormal state of deep unconsciousness. A coma may occur as the result of trauma to the head, disease (such as meningitis, stroke, or diabetes mellitus), or poisoning.

---

Other Word Forms

• comal
  adjective

Etymology

Origin of coma¹

First recorded in 1640–50, coma is from the Greek word kôma deep sleep

Origin of coma²

1660–70; < Latin: hair < Greek kómē

Explanation

Medically speaking, a coma is the state of protective deep sleep your body goes into when severely injured, as in a car crash. Daytime soap operas would be lost without a good coma every few weeks. Coma comes from the Greek koma meaning "deep sleep." As with so many words with medical or scientific origins, coma has been appropriated for a far wider range of uses. The zombie-like trance you fall into at family get-togethers like Thanksgiving? That too is a coma, though your chances of recovery are far better than from a real coma. Unless you happen to sit next to Aunt Sadie.

Example Sentences

"When you were in your induced coma your brain wasn't shut down," Pieter told Keenan.

From BBC • May 15, 2026

A number of intesive care patients have reported experiencing vivid dreams while in a coma and studies in Greece and Australia have explored this phenomenon.

From BBC • May 15, 2026

Keenan wanted to understand more about his memories of being in a coma, so the BBC arranged for him to meet consultant clinical psychologist Pieter du Toit, who is clinical director of the charity Brainkind.

From BBC • May 15, 2026

I went into septic shock and spent over a month in a medically induced coma.

From The Wall Street Journal • May 11, 2026

Right from his coma, he helped the four of us make wrongs right.

From "Because of Mr. Terupt" by Rob Buyea

Related Words

• oblivion
• slumber
• stupor
• trance