fetus

noun

fe·​tus ˈfē-təs How to pronounce fetus (audio)
: an unborn or unhatched vertebrate especially after attaining the basic structural plan of its kind
specifically : a developing human from usually two months after conception to birth compare embryo sense 1a

Examples of fetus in a Sentence

Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
In some cases, doctors must terminate a pregnancy to save the patient's life, particularly when the fetus cannot survive. Russel Honoré, Newsweek, 5 Mar. 2025 Other effects, such as developmental malformations in a fetus and cancer, have also been linked to this surfactant.1312 2. Anna Giorgi, Verywell Health, 4 Mar. 2025 It is used in medications to prevent haemolytic disease of the fetus and newborn (HDFN) — also known as rhesus disease — a potentially fatal disease that occurs when a pregnant person's blood is incompatible with that of their unborn baby, prompting their immune system to attack it. Rachel Treisman, NPR, 3 Mar. 2025 The previous record holder was Wigan’s Kevlar sculpture of a fetus, situated in a hollowed piece of hair. Sonja Anderson, Smithsonian Magazine, 28 Feb. 2025 See All Example Sentences for fetus

Word History

Etymology

Middle English, from Latin, act of bearing young, offspring; akin to Latin fetus newly delivered, fruitful — more at feminine

First Known Use

14th century, in the meaning defined above

Time Traveler
The first known use of fetus was in the 14th century

Browse Nearby Words

Cite this Entry

“Fetus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/fetus. Accessed 23 Mar. 2025.

Kids Definition

fetus

noun
fe·​tus ˈfēt-əs How to pronounce fetus (audio)
plural fetuses
: a young animal while in the body of its mother or in the egg especially in the later stages of development
especially : a developing human being in the uterus from usually two months after pregnancy occurs to birth compare embryo sense 1

Medical Definition

fetus

noun
fe·​tus
variants or chiefly British foetus
plural fetuses or chiefly British foetuses or foeti ˈfēt-ˌī How to pronounce fetus (audio)
: an unborn or unhatched vertebrate especially after attaining the basic structural plan of its kind
specifically : a developing human from usually two months after conception to birth compare embryo

More from Merriam-Webster on fetus

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