from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. 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.
  • n. Astronomy The nebulous luminescent cloud containing the nucleus and constituting the major portion of the head of a comet.
  • n. Botany A usually terminal tuft or cluster, especially a tuft of hairs on a seed, as on a willow or milkseed.
  • n. Physics A diffuse, comet-shaped image of a point source of light or radiation caused by aberration in the optical system.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. A state of sleep from which one may not wake up, usually induced by some form of trauma.
  • n. A cloud of dust surrounding the nucleus of a comet
  • n. A defect characterized by diffuse, pear-shaped images that should be points
  • n. A tuft or bunch, such as the assemblage of branches forming the head of a tree, a cluster of bracts when empty and terminating the inflorescence of a plant, or a tuft of long hairs on certain seeds.

from the GNU version of the Collaborative International Dictionary of English

  • n. A state of profound insensibility from which it is difficult or impossible to rouse a person. See carus.
  • n. The envelope of a comet; a nebulous covering, which surrounds the nucleus or body of a comet.
  • n. A tuft or bunch, -- as the assemblage of branches forming the head of a tree; or a cluster of bracts when empty and terminating the inflorescence of a plant; or a tuft of long hairs on certain seeds.

from The Century Dictionary and Cyclopedia

  • n. In pathology, a state of prolonged unconsciousness some what resembling sleep, from which the patient cannot be aroused, or can be aroused only partially, temporarily, and with difficulty; stupor.
  • n. In botany: The leafy head of a tree, or a cluster of leaves terminating a stem, as the leafy top of a pineapple.
  • n. The silky hairs at the end of some seeds, as of the willow-herb, Epilobium.
  • n. In astronomy, the nebulous hair-like envelop surrounding the nucleus of a comet.
  • n. In microscopy, the hazy fringe on the outline of a microscopic object seen when the lens is not free from spherical aberration.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. a state of deep and often prolonged unconsciousness; usually the result of disease or injury
  • n. (botany) a usually terminal tuft of bracts (as in the pineapple) or tuft of hairs (especially on certain seeds)
  • n. (astronomy) the luminous cloud of particles surrounding the frozen nucleus of a comet; forms as the comet approaches the sun and is warmed


Greek kōma, deep sleep.
Latin, hair, from Greek komē.
(American Heritage® Dictionary of the English Language, Fourth Edition)
From Ancient Greek κῶμα (kōma, "deep sleep"). (Wiktionary)
From Latin coma ("hair of the head"), from Ancient Greek κόμη (komē, "hair"). (Wiktionary)



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  • I've encountered a vendingmachine that certainly seemed not to be in a hurry and/or in a coma...but that eventually delivers the goods. And delicious goods they are....

    May 23, 2016

  • Inserting a coma can make all the difference in a sentence. For example:
    - vendingmachine is in a hurry.
    + vendingmachine is in a coma.

    May 22, 2016

  • Or maybe a false cognate?

    June 10, 2015

  • I know. I was trying to remember that, too. Is it just a false friend?

    June 10, 2015

  • doggone it, what's that word that means one spelling of two different words, usually with different etymologies. . .that's what coma seems to be.

    June 10, 2015

  • I just got comate as a random word--I had no idea coma can also mean hairy.

    June 10, 2015