fetus

noun

fe·​tus ˈfē-təs 

: 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

Now there was virtually no chance the fetus’s lungs would develop to reach the edge of viability in seven weeks. —Kavitha Surana, CNN Money, 28 May 2026

There was also a decrease in amniotic fluid, which protects the fetus and provides other benefits during pregnancy, the zoo said. —Julia Gomez, USA Today, 28 May 2026

Now there was virtually no chance the fetus’s lungs would develop to reach the edge of viability in seven weeks. —Kavitha Surana, ProPublica, 26 May 2026

The fetus was only 70 days old when the mother died of a bacterial infection. —Alex Morris, Rolling Stone, 19 May 2026

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

Rhymes for fetus

• foetus
• meatus
• thetis
• treatise
• caritas
• mellitus
• cellulitis
• margaritas
• tonsillitis

Kids Definition

fetus

noun

fe·​tus ˈfēt-əs 

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 

plural fetuses or chiefly British foetuses or foeti ˈfēt-ˌī 

: 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