fe·​tus | \ˈfē-təs \

Definition of fetus 

: 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 1b

Examples of fetus in a Sentence

Recent Examples on the Web

Toxoplasma courses through the body, targeting any combination of organs, including, in the case of females, the uterus, and for fetuses, the placenta. Kim Steutermann Rogers, Smithsonian, "How the Tiniest of Parasites is Taking Down the Mightiest of Monk Seals," 9 July 2018 One baby that would stand out at the Met Gala was the fetus currently gestating inside Cardi. New York Times, "In the Name of Cardi, Let Us Pray," 8 May 2018 Liz Dufour He was curled like a fetus in the tight space between the hatchback and backseat of his own blue 2001 Chrysler Town & Country minivan. Terry Demio, Cincinnati.com, "'They passed as many as 3 hospitals.' What's wrong with Good Sam 911 overdose laws?," 11 Apr. 2018 And the killing of female fetuses remains an issue. The Christian Science Monitor, "India’s swing in favor of girls," 17 Apr. 2018 And some of those will land before the bench, where a new conservative justice may be more open to arguments that the state’s obligation to protect the health of mother and fetus outweighs a woman’s constitutional right to privacy. Joe Fox, Washington Post, "What could happen if Roe v Wade gets struck down?," 29 June 2018 Depending on the extent of the separation, this may result in serious health complications for both mother and fetus, such as placenta abruption, which is what happened to me. Tara Shafer, Redbook, "I Lost a Baby at 33 Weeks — Now I'm Fighting to Spare Others the Same Pain," 19 June 2018 The 108 genes that make up the risk score are expressed at particularly high levels in the placenta, the study also found, and at higher levels in the placentas of male fetuses than female ones. Sharon Begley, STAT, "Schizophrenia ‘risk genes’ are not so risky if the mother’s pregnancy was healthy," 28 May 2018 All of Ireland's 40 voting regions tallied so far voted in favor of doing away with the amendment, which required authorities to defend the lives of a mother and a fetus equally. Bloomberg.com, "The Latest on Ireland’s Abortion Referendum," 26 May 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'fetus.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

See More

First Known Use of fetus

14th century, in the meaning defined above

History and Etymology for fetus

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

Keep scrolling for more

Learn More about fetus

Statistics for fetus

Last Updated

7 Nov 2018

Look-up Popularity

Time Traveler for fetus

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

See more words from the same century

Keep scrolling for more

More Definitions for fetus



English Language Learners Definition of fetus

: a human being or animal in the later stages of development before it is born


fe·​tus | \ˈfē-təs \

Kids Definition of fetus

: an animal not yet born or hatched but more developed than an embryo


variants: or chiefly British foetus \ ˈfēt-​əs \
plural fetuses or chiefly British foetuses or foeti\ ˈfēt-​ˌī \

Medical Definition of fetus 

: 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

Keep scrolling for more

Comments on fetus

What made you want to look up fetus? Please tell us where you read or heard it (including the quote, if possible).


playful or foolish behavior

Get Word of the Day daily email!

Test Your Vocabulary

Autumn Words of the Day 2018

  • a-top-down-image-of-road-through-an-autumn-forest
  • Which is a synonym of fugacious?
Name That Thing

Test your visual vocabulary with our 10-question challenge!


Test Your Knowledge - and learn some interesting things along the way.


Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!