cotyledon
cot.y.le.don or cot.y.le.don.ous \.ka:t-*l-'e-d-*n\ \-'e-d-n*l, -*n-*l\ \-'e-d-*n-.er-e-\ \-'e-d-*n-*s\ n [NL, fr. Gk kotyle-do-n cup-shaped hollow, fr. kotyle- cup] 1: a placental lobule 2: the first leaf or one of the first pair or whorl of leaves developed by the embryo of a seed plant - cot.y.le.don.al aj