Main Entry: pro·neph·ros

Pronunciation: \(ˌ)prō-ˈne-frəs, -ˌfräs\

Function: noun

Etymology: New Latin, from Greek pro- + nephros kidney — more at nephritis

Date: 1881

: either member of the first and most anterior pair of the three successive paired vertebrate renal organs that functions in the adults of amphioxus and some lampreys, functions temporarily in larval fishes and amphibians, and is present but nonfunctional in embryos of reptiles, birds, and mammals — compare mesonephros, metanephros

— pro·neph·ric \-frik\ adjective