Reconstruction:Proto-Germanic/feþrō

From Pre-Germanic *péth₂reh₂, extended from the nominative stem of the Proto-Indo-European heteroclitic noun *péth₂r̥ ~ pth₂én-, from *peth₂- (to fly).[1] Compare Latin penna from Proto-Italic *petnā, which is a similar extension but from the oblique stem.