fetus
Pluralfetuses, fetus
UK spellingfoetus
- 1An unborn or unhatched young animal that has developed its basic body form, especially a human more than eight weeks after conception.
Researchers are studying how a mother's diet in late pregnancy affects the growing fetus.
The scan showed two fetuses, each with a strong heartbeat.
UsagePlural fetuses (not
incorrect: feti). British English often spells it foetus.Note
Embryo and fetus divide a pregnancy between them: through the eighth week after fertilization the developing human is an embryo, after it a fetus, at the end of a sequence that runs from zygote through morula and blastocyst.
Checked 1 Nov 2026 · 2 facts
- Embryonic development is followed by fetal development until birth. embryology.med.unsw.edu.au
- Early development proceeds from zygote through morula and blastocyst. embryology.med.unsw.edu.au
- 2A newborn infant.
Note
Older writers could use the word for a child already born. John Locke, in An Essay Concerning Human Understanding (1689), asks what we should call an oddly shaped fœtus, spelled with the old letter œ. A modern reader hears only a human before birth, so this use belongs to reading old texts, not to writing new ones.
Checked 3 Nov 2026 · 5 facts
- Older writers used fetus for a child already born. en.wiktionary.org
- John Locke wrote An Essay Concerning Human Understanding. en.wikipedia.org
- The book was first published in 1689. en.wikipedia.org
- Locke discusses whether an oddly shaped newborn should be called a human. en.wikisource.org
- The word in Locke's passage is printed with œ. en.wikisource.org
Use it in a sentence
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Origin
Fawn is a doublet of this word, which English borrowed in learned use from Latin fētus, meaning "offspring."
Checked 1 Nov 2026 · 3 facts
- Fawn is a doublet of fetus. en.wiktionary.org
- English borrowed fetus in learned use from Latin fētus. en.wiktionary.org
- Latin fētus means offspring. en.wiktionary.org