An Etymological Dictionary of the German Language/Geiß
Geiß, f., ‘goat, roe,’ from the equiv. MidHG. and OHG. geiȥ, f,; corresponding to Goth. gaits, OIc. geit, AS. gât, E. goat, Du. geit; also a dimin. Goth. gaitein, AS. gœ̂ten, OHG. geizzîn, n., ‘kid’ (see Schwein). Primit. allied to Lat. haedus from older ghaido-s (see Ritze and Ziege). In common with Slav., OTeut. has a different word for Ziege; comp. MidDu. hoekijn, AS. hêcen, ‘kid,’ akin to OSlov. koza, ‘goat.’