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bean seed germinating
1. 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.
2. 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-ĕr′ē), cot′y·le′don·al (-ēd′n-əl), cot′y·le′do·nous (-ēd′n-əs) adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.