# fetus in fetu

> English word · Noun

## Definitions
1. A fetus growing inside the body of another fetus, either from an unsuccessful twin pregnancy, or as a tumorlike growth.

## Etymology
From Latin fētus in fētū.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/fetus-in-fetu