coma

¹

[koh-muh]

noun

plural

comas 

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

coma

²

[koh-muh]

noun

plural

comae 

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

/ 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

²

/ 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

¹

plural

comas 

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

²

plural

comae 

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

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

Word History and Origins

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

Word History and Origins

Origin of coma¹

C17: from medical Latin, from Greek kōma heavy sleep; related to Greek koitē bed, perhaps to Middle Irish cuma grief

Origin of coma²

C17: from Latin: hair of the head, from Greek komē

Example Sentences

They took him to al-Shifa hospital, where Hadeel says she was told her husband had a skull fracture and was in a coma.

Read more on BBC

Or perhaps you’ve spent the last many months in a coma, or cut off from the world in the frozen tundra of Antarctica.

Read more on Los Angeles Times

A woman who went into hospital for a planned Caesarean section and ended up in a coma for four days has said she remains traumatised by her experience.

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The 21-year-old died on Thursday after several days in an induced coma.

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"After sustaining a significant brain injury last Saturday, Billy Vigar was put into an induced coma," the family said.

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Related Words

• oblivion 
• slumber 
• stupor 
• trance