cotyledon

cot·y·le·don

noun \ˌkä-tə-ˈlē-d^ən\

Definition of COTYLEDON

1

: a lobule of the mammalian 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 \-ˈlē-də-ˌner-ē\ adjective

Origin of COTYLEDON

New Latin, from Greek kotylēdōn cup-shaped hollow, from kotylē cup, anything hollow

First Known Use: 1540

cot·y·le·don

noun \ˌkät-^əl-ˈēd-^ən\   (Medical Dictionary)

Medical Definition of COTYLEDON

1

: a lobule of a mammalian 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 \-ˈēd-^ən-ˌer-ē\ adjective

cotyledon

noun    (Concise Encyclopedia)

(Top) Monocotyledon (internal structures of a corn seed with stages of germination). Nutrients are …—© Merriam-Webster Inc.

Seed leaf within the embryo of a seed that provides energy and nutrients for the developing seedling. After the first true leaves have formed, they wither and fall off. Flowering plants whose embryos have a single cotyledon are grouped as monocots, or monocotyledonous plants; embryos with two cotyledons are grouped as dicots, or dicotyledonous plants. Unlike flowering plants, gymnosperms usually have several cotyledons rather than one or two.