1
: a state of profound unconsciousness caused by disease, injury, or poison
2
: a state of mental or physical sluggishness : torpor
plural comae
ˈkō-ˌmē 
-ˌmī
1
: a tufted bunch (as of branches, bracts, or seed hairs)
2
: the head of a comet consisting of a cloud of gas and dust and usually containing a nucleus
3
: an optical aberration in which the image of a point source is a comet-shaped blur
Examples of coma in a Sentence
Recent Examples on the Web
Deirdre Bardolf, FOXNews.com, 25 Oct. 2025
The composite image shows the nucleus or icy, rocky central core of 3I/ATLAS as a large and black dot, along with a white glow — the comet's coma, or atmosphere.
—Elizabeth Howell, Space.com, 24 Oct. 2025
While the nucleus may be a few kilometers across, the coma can be tens of thousands of kilometers wide, which is bigger than some planets.
—Phil Plait, Scientific American, 23 Oct. 2025
Ball subsequently caught pneumonia and developed sepsis, which led to him being placed in an induced coma during a seven month hospital stay.
—Gil Kaufman, Billboard, 23 Oct. 2025
See All Example Sentences for coma
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Noun
The site became overcrowded and used controversial treatments such as electroshock and insulin coma therapy, according to local reports, and since its abandonment, many visitors report paranormal activity in the former ward buildings.
—Deirdre Bardolf, FOXNews.com, 25 Oct. 2025
The composite image shows the nucleus or icy, rocky central core of 3I/ATLAS as a large and black dot, along with a white glow — the comet's coma, or atmosphere.
—Elizabeth Howell, Space.com, 24 Oct. 2025
While the nucleus may be a few kilometers across, the coma can be tens of thousands of kilometers wide, which is bigger than some planets.
—Phil Plait, Scientific American, 23 Oct. 2025
Ball subsequently caught pneumonia and developed sepsis, which led to him being placed in an induced coma during a seven month hospital stay.
—Gil Kaufman, Billboard, 23 Oct. 2025
See All Example Sentences for coma
Cite this Entry
“Coma.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/coma. Accessed 28 Oct. 2025.
Copy CitationKids Definition
coma
1 of 2 noun
co·ma
ˈkō-mə
: a sleeplike state of unconsciousness caused by disease, injury, or poison
coma
2 of 2 noun
plural comae
-ˌmē
-ˌmī
: the head of a comet made up of a cloud of gas and dust and usually containing a nucleus
Etymology
Noun
scientific Latin, from Greek kōma "deep sleep"
Noun
from Latin coma "hair," from Greek komē "hair" — related to comet
Medical Definition
coma
noun
co·ma
ˈkō-mə
: a state of profound unconsciousness caused by disease, injury, or poison
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