INCUMBENT COMA

Before we had the noun coma, speakers of Middle English used the term false sleep to define the state of consciousness. Then, in 1646, it was attested in an epidemiology textbook which said that sneezing is of "good signality" during capital-C Comas, and usage has been steadily increasing since then.  This was a Latinized form of the Ancient Greek word koma, meaning "deep sleep" in general. Finally, the exact etymology of koma is unknown, but it's thought to maybe trace to the Proto-Indo-European root kumb, which would make it a distant relative of incumbent ("one who lies down"). Coma also has a second meaning of "head of a comet"; this is entirely unrelated and traces to Ancient Greek kome, which referred to head hairs and also has an unknown etymology.