Carotid
early 17th century: from French carotide or modern Latin carotides, from Greek karōtides, plural of karōtis ‘drowsiness’, from karoun ‘stupefy’ (because compression of these arteries was thought to cause stupor).
wiktionary
Borrowed from French carotide or New Latin carōtides, from Ancient Greek κᾰρωτῐ́δες(karōtídes, “carotid arteries”), from κᾰρόω(karóō, “to plunge into deep sleep or torpor”) + -τῐ́δες(-tídes, plural nominal suffix), from the fact that the carotid artery supplies blood to the brain, and interruption of this flow causes loss of consciousness.
etymonline
carotid (adj.)
1540s, "pertaining to the two great arteries of the neck," from Greek karotides "great arteries of the neck," plural of karotis, from karoun "plunge into sleep or stupor," because compression of these arteries was believed to cause unconsciousness (Galen). But if this is folk etymology, the Greek word could be from kara "head," related to kranion "skull, upper part of the head," from PIE root *ker- (1) "horn; head."
