noun, plural met·a·neph·roi [met-uh–nef-roi] /ˌmɛt əˈnɛf rɔɪ/. Embryology.
- one of the three embryonic excretory organs of higher vertebrates, becoming the permanent and functional kidney.
noun plural -roi (-rɔɪ)
- the last-formed posterior part of the embryonic kidney in reptiles, birds, and mammals, which remains functional in the adultSee also pronephros, mesonephros
n. pl. met•a•neph•roi (-roi′)
- The third and final excretory organ that develops in a vertebrate embryo. In birds, reptiles, and mammals it replaces the mesonephros as the functional excretory organ and develops into the adult kidney.