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

Ancient Mesopotamians did not have obstetric medicine, reliable methods for assessing the health of a fetus in utero, gynecological surgery, or neonatal care. — Eleanor Johnson, Harpers Magazine, 22 Sep. 2026

The medical examiner found the fetus had normal development for 20 weeks' gestation, weighing less than a pound. — Jericka Duncan, CBS News, 15 Sep. 2026

Aspirin and ibuprofen can pose serious risks to the mother and fetus, including miscarriage. — Jen Christensen, CNN Money, 8 Sep. 2026

The production of some vaccines involves growing viruses in human cell cultures from two fetuses aborted in the 1960s, according to the American Academy of Pediatrics. — Finch Walker, USA Today, 27 Aug. 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