cotyledon (n.)youdaoicibaDictYouDict[cotyledon 词源字典]
from 1540s, in various sense, from Latin cotyledon "pennywort, navelwort," from Greek kotyledon "cup-shaped cavity," from kotyle "hollow thing, small vessel," also the name of a small liquid measure (nearly a half-pint); which is of uncertain origin. Botanical sense is 1776, from Linnaeus (1751).[cotyledon etymology, cotyledon origin, 英语词源]