placenta

Etymology

It is borrowed from New Latin placenta,^[2][3][4] recorded in this sense from 1559,^[2] in full placenta uterina (“uterine cake”),^[5][6][7] a name that Etymonline and Klein say the Italian anatomist Realdo Colombo gave it in the 16th century.^[5][8] It is a transferred use of Latin placenta (“a kind of flat cake”),^[2][7][3] which is from Ancient Greek πλακόεντα (plakóenta), the accusative of πλακόεις (plakóeis, “flat cake”),^[8][6][3] contracted πλακοῦς (plakoûs),^[2][6] from πλάξ (pláx, “flat plate, flat surface”).^[2][8][7][9] Etymonline traces it to Proto-Indo-European *plak- (“to be flat”).^[5] Klein thinks the Latin form was influenced by Latin placeō (“to please”).^[8] The same Latin word gave French placenta (1642) and Italian placenta.^[2]

Earliest recorded meaning

The organ that joins the fetus to the wall of the womb: 1638, in A. Read's manual of anatomy.^[2] Merriam-Webster also dates the word to 1638.^[4] Barnhart and Etymonline instead find it first in botany, in the 1670s (in Nehemiah Grew), and for the organ in 1691 or the 1690s,^[6][5] and the Shorter Oxford and Hoad date it to the 17th century.^[10][9]

Semantic evolution

The name compares the organ to a flat round cake: its use for the afterbirth is a post-classical development, inspired by its shape.^[7][11][5] In botany the word was applied from 1681 to the part of the ovary where the ovules are attached, and in ferns to the point where the spore cases arise.^[2][12]

Timeline

• 1638 – the organ that joins the fetus to the womb.^[2][4] Barnhart dates this sense to 1691.^[6]
• 1677 – in botany, the ovary tissue that bears the ovules, in Nehemiah Grew.^[6] The OED's first botanical record is from 1681.^[2]

Meanings

Noun

1. The organ, rich in blood vessels, that forms in the uterus during pregnancy and joins the fetus to the mother, supplying it with oxygen and food and taking away its waste: The placenta is delivered after the baby.^[4][13][2]
2. (botany) The part of a plant's ovary to which the ovules are attached.^[4][2][13]

Word family

• placental
• placentation
• subplacenta

Related words

• plank
• fluke

References

1. ^ a b Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j k l Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
4. ^ a b c d e Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
5. ^ a b c d e Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
6. ^ a b c d e f Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
7. ^ a b c d Ayto, John (2005), Word Origins: The Secret Histories of English Words from A to Z, 2nd ed., London: A & C Black
8. ^ a b c d Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
9. ^ a b Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
10. ^ Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
11. ^ Cresswell, Julia (2021), Oxford Dictionary of Word Origins, 3rd ed., Oxford: Oxford University Press
12. ^ Barnhart, Robert K., ed. (1995), The Barnhart Concise Dictionary of Etymology, New York: HarperCollins
13. ^ a b Collins English Dictionary (2023), Glasgow: HarperCollins