Alternative spellings (UK) foetus (old, no longer used) fœtus Pronunciation IPA (key): /ˈfiːtəs/ Audio (UK)(file) Noun Singular fetus Plural fetuses or feti (countable) A fetus is a human embryo after 8 weeks of gestation. Related words fetalWikiwand - on Seamless Wikipedia browsing. On steroids.Remove ads