The Collaborative International Dictionary
Metanephros
Metanephros \Met`a*neph"ros\, n. [NL., fr. Gr. ? behind + ? kidney.] (Anat.) The most posterior of the three pairs of embryonic renal organs developed in many vertebrates.
Wiktionary
metanephros
n. (context anatomy English) The most posterior of the three pairs of embryonic renal organs developed in many vertebrates.