An Etymological Dictionary of the German Language/Annotated/Galle
Galle (1.), feminine, ‘gall, bile,’ from the equivalent Middle High German galle, Old High German galla, feminine; common to Teutonic in the same sense (only in Gothic is the weak neuter *gallô not recorded); compare Old Saxon galla, Dutch gal, Anglo-Saxon gealla, Old Icelandic gall, neuter. Like a great number of terms relating to the body (see Fuß, Herz, Niere, Nase, Ohr), Galle too has numerous correspondences in the cognate languages, which points to the antiquity of the Aryan term (Gothic *gallin- or *galzin-, from pre-Teutonic ghal-); compare Greek χολή, χόλος, Latin fel, fellis, neuter, ‘gall.’ Many etymologists connect the word with gelb (Old High German gëlo), as if gall was named from its colour; Old Slovenian žlŭčĭ, ‘gall’ (from *gĭlkĭ), is certainly allied to Russian želknutĭ, ‘to turn yellow.’ Galle (2.), feminine, ‘barbel,’ from Middle High German galle, feminine, ‘swelling above the knee on the hind-leg of a horse’; compare English gall (swelling, sore spot, gall-nut); it is questionable whether Gall-Apfel is allied to the word. Also in Romance, Italian galla and Spanish agulla, signify ‘swelling, tumour, gall-nut.’ Hence the Latin-Romance galla, ‘gall-nut,’ was perhaps the source of the Teutonic terms. Yet it is possible that the foreign word has been confused with a Teutonic word similar in sound, especially since Swedish dialects also have a term gräsgaller, ‘swelling on the hoof of a horse.’