fetus

Forms

• foetus (UK)

Etymology

It is borrowed from Latin fētus (“a bearing or hatching of young; offspring, young”),^[2][3][4][5] formed with the suffix -tus from the same base as fēmina (“woman”),^[2][4] from Proto-Indo-European *dhē(i)- (“to suck, suckle”).^[3][5][6] Merriam-Webster connects it with a Latin adjective of the same form, meaning pregnant, fruitful.^[7][8] The same base appears in fēcundus (“fruitful”), fēnus (“proceeds”) and fīlius (“son”).^[6][4] The OED compares fetus, feto and feto,^[2] and Skeat linked it instead with the root of fuī (“I was”).^[9]

Earliest recorded meaning

The offspring of a human or other animal while it develops in the womb or egg: before 1398, in John Trevisa's translation of Bartholomaeus Anglicus.^[2][4][3]

Semantic evolution

In Latin fetus meant chiefly the bearing of young or a brood, and only sometimes the newborn creature itself; it was also used of plants for fruit or produce.^[3] In English it named the young in the womb from the start,^[3][2] tending to mean the later stages of development, after the embryo;^[3][10][7] it has been used figuratively since 1632.^[2] Johnson (1755) defined it as "any animal in embrio; any thing yet in the womb".^[11] The derived adjective fetal is first recorded in 1811.^[4]

Timeline

• before 1398 – the young in the womb or egg.^[2][4]
• 1632 – figurative use.^[2]
• 17th century – the spelling foetus appears.^[2]
• 1811 – fetal.^[4]

Meanings

Noun

1. The unborn young of a mammal or other vertebrate in the later stages of its development, when it has the main features of its kind; in humans, from about the end of the second month of pregnancy until birth.^[10][7][2]
2. Something in an early, undeveloped stage (figurative).^[2]

Word family

• fetal
• feticide
• superfetation

Related words

• feminine
• female
• fecund
• filial
• effete

Usage notes

The spelling foetus is recorded from the 17th century and was long the standard British form;^[2] fetus is now standard in technical use everywhere, but foetus survives in British English outside technical contexts.^[2][10] The oe spelling is an unetymological Latinism: Latin inscriptions have only fētus, though manuscripts have both.^[3][2][6] The plural is fetuses;^[7] feti and foeti follow Latin second-declension nouns, though the Latin word is not one.^[2][7]

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j k l m n o Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d e f g Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
4. ^ a b c d e f g Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
5. ^ a b The American Heritage Dictionary of the English Language (online 2024), 5th ed., Boston: Houghton Mifflin Harcourt
6. ^ a b c Klein, Ernest. A Comprehensive Etymological Dictionary of the English Language. 2 vols. Amsterdam: Elsevier, 1966–1967.
7. ^ a b c d e Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
8. ^ Partridge, Eric (1966), Origins: A Short Etymological Dictionary of Modern English, 4th ed., London: Routledge & Kegan Paul
9. ^ Skeat, Walter W. (1911), A Concise Etymological Dictionary of the English Language, new ed., Oxford: Clarendon Press
10. ^ a b c Collins English Dictionary (2023), Glasgow: HarperCollins
11. ^ Johnson, Samuel (1755), A Dictionary of the English Language, London; 4th ed. 1773; Johnson's Dictionary Online, ed. Beth Rapp Young et al.