(ˈ)prō|nefrəs, -ˌfräs noun
also pro·neph·ron -_frən, -ˌfrän
( plural proneph·roi -ˌfrȯi ; also proneph·ra -_frə)
Etymology: New Latin, from pro- (I) + Greek nephros kidney — more at nephritis
: one of the anterior of the three pairs of embryonic renal organs of higher vertebrates