"red variety of chalcedony," 1560s, a variant of corneline (c. 1400), from Old French corneline (Modern French cornaline), diminutive of corneola, which is probably from Vulgar Latin *cornea, from Latin cornus, name of a type of berry (see cornel and compare carnelian).
corn-crib
corn-dodger
corn-dog
cornea
cornel
cornelian
Cornelius
corner
cornered
cornerstone
cornet