cotyledon n.

from 1540s in physiology, later in botany, used in various sense, from Latin cotyledon "pennywort, navelwort," from Greek kotyledon "cup-shaped cavity," used of various holes, also "sucker, suction cup," also a plant name, from kotylē "bowl, dish, small cup," also the name of a small liquid measure (nearly a half-pint), in transferred use, "socket, especially of the hip-joint;" a word of uncertain origin [Beekes finds it probably Pre-Greek]. Botanical sense is 1776, from Linnaeus (1751). Related: Cotyledonal.