We're working on a new site. Click here to get a sneak preview.
Medical Dictionary


noun cot·y·le·don \ˌkät-əl-ˈēd-ən\

Medical Definition of COTYLEDON

:  a lobule of a mammalian placenta
:  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


How to use a word that (literally) drives some people nuts.
Test your vocab with our fun, fast game
Ailurophobia, and 9 other unusual fears