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.
Ultrasound studies indicate that a fetus’s dominant hand is decided before its brain even connects to its limbs. — Quanta Magazine, 13 July 2026 The Tarrant County Medical Examiner’s Office will determine the fetus’ identity and the circumstances that led its death. — Fousia Abdullahi, Fort Worth Star-Telegram, 10 July 2026 An ultrasound revealed that Geno had complete heart block and hydrops fetalis — a serious condition that causes abnormal fluid buildup in multiple areas of the fetus’s body, leading to severe swelling. — Paloma Chavez, PEOPLE, 6 July 2026 It’s often deployed in monitoring the development of a fetus during pregnancy and can have diagnostic uses as well. — Joshua P. Cohen, Forbes.com, 2 July 2026 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

Rhymes for fetus

See All Rhymes for fetus

Browse Nearby Words

fettuccine Alfredo
fetus
feu
See all Nearby Words

Cite this Entry

“Fetus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/fetus. Accessed 22 Jul. 2026.

Copy Citation

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
ˈfēt-əs How to pronounce fetus (audio)
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

Nglish: Translation of fetus for Spanish Speakers

Britannica.com: Encyclopedia article about fetus

Last Updated: - Updated example sentences
Love words? Need even more definitions?

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

More from Merriam-Webster

Word of the Day

Listen to the pronunciation of stalwart

See Definitions and Examples »

Popular in Grammar & Usage

See More

Merriam-Webster’s Great Big List of Words You Love to Hate

'A' or 'an'? What about before 'h'? An Indefinite Article Guide

Do you 'say your piece' or 'say your peace'?

Why is '-ed' sometimes pronounced at the end of a word?

Commonly Misspelled Words
See More

Popular in Wordplay

See More

14 Phobias You Probably Haven't Heard Of

It's a Scorcher! Words for the Summer Heat

The Longest Long Words List

Ten Words Ending with a Silent ‘T’

Why do we say 'fly off the handle'?
See More

Popular

See More

Merriam-Webster’s Great Big List of Words You Love to Hate

14 Phobias You Probably Haven't Heard Of

It's a Scorcher! Words for the Summer Heat
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
The Missing Letter A daily crossword with a twist
thumbnail graphic with text word of the day quiz
Weekly "Word of the Day" Quiz See how well you know each Word of the Day for Ju...
See All