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coma

 - 10 dictionary results

co⋅ma

1[koh-muh]
–noun, plural -mas.
a state of prolonged unconsciousness, including a lack of response to stimuli, from which it is impossible to rouse a person.

Origin:
1640–50; < Gk kôma deep sleep

co⋅ma

2[koh-muh]
–noun, plural -mae [-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.
a. a tuft of silky hairs at the end of a seed.
b. the leafy crown of a tree; cluster of leaves at the end of a stem.
c. a terminal cluster of bracts, as in the pineapple.

Origin:
1660–70; < L: hair < Gk kómē
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2009.
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co·ma 1   (kō'mə)   
n.   pl. co·mas
A state of deep, often prolonged unconsciousness, usually the result of injury, disease, or poison, in which an individual is incapable of sensing or responding to external stimuli and internal needs.

[Greek kōma, deep sleep.]
co·ma 2   (kō'mə)   
n.   pl. co·mae (-mē)
  1. Astronomy The nebulous luminescent cloud containing the nucleus and constituting the major portion of the head of a comet.

  2. Botany A usually terminal tuft or cluster, especially a tuft of hairs on a seed, as on a willow or milkseed.

  3. Physics A diffuse, comet-shaped image of a point source of light or radiation caused by aberration in the optical system.


[Latin, hair, from Greek komē.]
co'mal adj.
The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2009 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Cultural Dictionary

coma [(koh-muh)]

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.

The American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Word Origin & History

coma 
1646, from Gk. koma (gen. komatos) "deep sleep." Comatose first recorded 1755.
Online Etymology Dictionary, © 2001 Douglas Harper
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Medical Dictionary

Main Entry: co·ma
Pronunciation: 'kO-m&
Function: noun
: a state of profound unconsciousness caused by disease, injury, or poison
Merriam-Webster's Medical Dictionary, © 2002 Merriam-Webster, Inc.
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Medical Dictionary

coma co·ma (kō'mə)
n.
A state of profound unconsciousness in which an individual is incapable of sensing or responding to external stimuli.

The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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Science Dictionary
coma 1   (kō'mə)  Pronunciation Key 
Plural comas
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   (kō'mə)  Pronunciation Key 
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.). See more at comet.

  2. 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.


The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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