coma

¹

[ koh-muh ]

noun

, plural co·mas.

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 co·mae [koh, -mee].

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

/ kō′mə /

, Plural comae kō′mē

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

/ kō′mə /

, 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

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.

Derived Forms

• ˈcomal, 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 new objective marker like this could help to improve the practice of anesthesia and treatments for coma patients.

From Quanta Magazine

He has been jailed more than ten times, spent hundreds of days in police custody since 2011, and was left in a coma after being poisoned by a powerful nerve agent last year.

From Time

Silca was transported to the hospital and remained in a coma until he died a month later.

From Voice of San Diego

Silva was transported to the hospital and remained in a coma until he died a month later.

From Voice of San Diego

With Shonray in a medically induced coma, Shonte checked in with her sister’s nurses daily and visited twice a week, every Thursday and Sunday.

From ProPublica

The peace process is in a coma; and ISIS, Hamas, Assad, Hezbollah, and the Iranian mullahs make Israel look like the good guys.

From The Daily Beast

Everything changes when Rick slips into a coma after being shot while pursuing a criminal.

From The Daily Beast

For Rick, who awakens from his coma months after the dead have risen, the world changes overnight.

From The Daily Beast

While he was in a coma for seven days, his consciousness entered a series of transcendent realms.

From The Daily Beast

Nine months later, he awakens from his coma with washboard abs and the ability to run really fast.

From The Daily Beast

In diabetes its presence is a grave symptom and often forewarns of approaching coma.

From Project Gutenberg

He then retired into solitude near Coma, passing his time in manual labour, prayer, and study.

From Project Gutenberg

It's more of a coma, something like the hibernation of a bear or a possum.

From Project Gutenberg

I am glad to have been aroused by so sympathetic a spirit from the coma of thirty years.

From Project Gutenberg

The fatal coma may last even when the person has been removed from the gas from hours to days.

From Project Gutenberg

Related Words

• oblivion
• slumber
• stupor
• trance