cotyledon

American  

[kot-l-eed-n] / ˌkɒt lˈid n /

noun

Botany.

1. the primary or rudimentary leaf of the embryo of seed plants.

2. Anatomy. any of several lobules of the placenta.

---

cotyledon British  

/ ˌkɒtɪˈliːdən /

noun

1. a simple embryonic leaf in seed-bearing plants, which, in some species, forms the first green leaf after germination

2. a tuft of villi on the mammalian placenta

---

cotyledon Scientific  

/ kŏt′l-ēd′n /

1. 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.

2. Also called seed leaf

3. See more at eudicotyledon monocotyledon

---

Other Word Forms

• cotyledonal adjective
• cotyledonary adjective
• cotyledonous adjective
• noncotyledonal adjective
• noncotyledonary adjective
• noncotyledonous adjective
• pseudocotyledonal adjective
• pseudocotyledonary adjective

Etymology

Origin of cotyledon

1535–45; < Latin: navelwort < Greek kotylēdṓn a plant (probably navelwort), literally, a cuplike hollow, derivative of kotýlē cup

Example Sentences

In five days, the “baby” cotyledon leaves were up, with the “true” notched tomato leaves following at day 10.

From Seattle Times • Jan. 27, 2023

Swinger says the sprout, called a cotyledon, only exists for a few days and once it grew slightly the birds didn’t want to eat it anymore.

From Washington Times • Jul. 17, 2016

The seed germinates and thousands of cotyledon leaves appear like fairy umbrellas, from the waste of the dead leaves.

From A West Country Pilgrimage by Phillpots, Eden

There is some difference of opinion as to which structure or structures represent the cotyledon.

From Encyclopaedia Britannica, 11th Edition, Volume 12, Slice 3 "Gordon, Lord George" to "Grasses" by Various

As their name indicates, there is but one cotyledon or seed leaf, and the leaves from the first are alternate.

From Elements of Structural and Systematic Botany For High Schools and Elementary College Courses by Campbell, Douglas Houghton