Definition of cotyledon in English:

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Pronunciation: /ˌkɒtɪˈliːd(ə)n/


1 Botany An embryonic leaf in seed-bearing plants, one or more of which are the first leaves to appear from a germinating seed.
Example sentences
  • The cotyledons are the ‘seed leaves’ produced by the embryo.
  • However, protein biosynthesis in the axis organs and cotyledons of dicotyledonous seeds commences much earlier.
  • Mutants of this class display shortened hypocotyls and small cotyledons after irradiation of seed.
2A succulent plant of the stonecrop family, some kinds of which are grown as ornamentals.
  • Genus Cotyledon and related genera, family Crassulaceae: several species.



Example sentences
  • Three chlorophyll readings were made and averaged on the middle leaflet of the first trifoliate of soybean, the second true leaf of lettuce (counting up from the cotyledonary leaves) and the second leaf of wheat.
  • Seedlings at the vegetative cotyledonary stage, about 7-10 days old, were transplanted into plastic pots containing the same medium.
  • Further development of cotyledonary embryo showing closed vascular system and characteristic cotyledonary notches.




Mid 16th century (denoting a patch of villi on the placenta of mammals): from Latin, 'navelwort' (which has cup-shaped leaves), from Greek kotulēdōn 'cup-shaped cavity', from kotulē 'cup'.

Words that rhyme with cotyledon

cedarn, dicotyledon, Eden, monocotyledon, Sweden

For editors and proofreaders

Line breaks: coty|le¦don

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