cot·y·le·don   (kŏt'l-ēd'n)    n.   Botany A leaf of the embryo of a seed plant, which upon germination either remains in the seed or emerges, enlarges, and becomes green. Also called seed leaf. Anatomy One of the lobules constituting the uterine side of the mammalian placenta, consisting mainly of a rounded mass of villi. [Latin cotylēdōn, navelwort, from Greek kotulēdōn, from kotulē, hollow object.] cot'y·le'don·ar'y (-ēd'n-ěr'ē), cot'y·le'don·al (-ēd'n-əl), cot'y·le'do·nous (-ēd'n-əs) adj.

Cotyledon

Cot`y*le"don\ (k?t`?-l?"d?n), n. [Gr.??? a cupshaped hollow, fr. ???. See Cotyle.]

1. (Anat.) One of the patches of villi found in some forms of placenta.

2. (Bot.) A leaf borne by the caulicle or radicle of an embryo; a seed leaf.

Note: Many plants, as the bean and the maple, have two cotyledons, the grasses only one, and pines have several. In one African plant (Welwitschia) the cotyledons are permanent and grow to immense proportions.

Main Entry: cot·y·le·don
Pronunciation: "kät-^&l-'Ed-^&n
Function: noun
1 : a lobule of amammalian placenta
2 : the first leaf or one of the first pair or whorl of leaves developed by the embryo of a seed plant or of some lower plants (as ferns) —cot·y·le·don·ary /-'Ed-^&n-"er-E/ adjective

cotyledon cot·y·le·don (kŏt'l-ēd'n)
n.

1. One of the lobules constituting the uterine side of the placenta, consisting mainly of a rounded mass of villi.
2. A leaf of the embryo of a seed plant, which, upon germination either remains in the seed or emerges, enlarges, and becomes green; a seed leaf.

cotyledon   (kŏt'l-ēd'n)  Pronunciation Key  A leaf of the embryo of a seed-bearing plant. Most cotyledons emerge, enlarge, and become green after the seed has germinated. Cotyledons either store food for the growing embryo (as in monocotyledons) or absorb food that has been stored in the endosperm (as in other angiosperms) for eventual distribution to the growing parts of the embryo. Also called seed leaf. See more at eudicotyledon, monocotyledon.