There are 2 definitions of coma in English:

coma1

Syllabification: co·ma
Pronunciation: /ˈkōmə
 
/

noun

A state of deep unconsciousness that lasts for a prolonged or indefinite period, caused especially by severe injury or illness: a road crash left him in a coma figurative a victim of a legislative coma
More example sentences
  • Conversely, the recovery of people from what we would call comas or deep sleep could be interpreted as an example of miraculous resurrection, perhaps accounting in part for the enduring popularity of saintly healing.
  • He had been in a deep coma at the Royal Hospital for Neurodisability after suffering severe brain damage.
  • The highest possible score is 15, and the lowest possible score is three, which indicates the most severe, deep coma.
Synonyms
state of unconsciousness; Medicinepersistent vegetative state

Origin

mid 17th century: modern Latin, from Greek kōma 'deep sleep'; related to koitē 'bed' and keisthai 'lie down'.

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Word of the day dissonant
Pronunciation: ˈdɪs(ə)nənt
adjective
lacking harmony

There are 2 definitions of coma in English:

coma2

Syllabification: co·ma
Pronunciation: /ˈkōmə
 
/

noun (plural comae /ˈkōmē/)

Astronomy
1A diffuse cloud of gas and dust surrounding the nucleus of a comet.
More example sentences
  • Rosetta's instruments will analyse the gases and dust grains in the coma that forms when the comet becomes active, as well as the interaction with the solar wind.
  • As it approaches the Sun, heat causes ices in the nucleus to sublimate, creating a cloud of gas and dust known as the coma.
  • The second explanation is that the X-rays are just solar X-rays scattered by the dust present in the coma.
1.1 Optics Aberration that causes the image of an off-axis point to be flared like a comet.
More example sentences
  • These Seidel sums correspond to spherical aberration, coma, astigmatism, Petzval curvature and distortion.
  • For the first time in optical design, aberration, diffraction and coma were described and understood.
  • The light from the null corrector goes to the mirror under test, and the alignment consists of pointing the corrector so that the return image is free of coma.

Origin

early 17th century (as a botanical term): via Latin from Greek komē 'hair of the head'.

Definition of coma in: