Definition of protonephros in English:

protonephros

(also protonephron)

noun

rare Embryology Zoology

Origin

Late 19th century; earliest use found in Haeckel's Evolution of Man. Originally as protonephron from scientific Latin protonephron from proto- + ancient Greek νεϕρός kidney.

Pronunciation

protonephros

/ˌprəʊtə(ʊ)ˈnɛfrɒs/