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

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.

From BBC

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

From BBC

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

From BBC

But after being taken to hospital, she suffered two heart attacks and fell into a coma, with the next three months a complete blank.

From BBC

The disease begins with seizures, cognitive decline and involuntary muscle spasms, and progresses to dementia, coma and eventually death.

From Los Angeles Times

Related Words

• oblivion 
• slumber 
• stupor 
• trance