Lewis & Short

Armŏrĭcae (later form Arēmŏrĭ-cae, Aus. Ep. 9, 35; id. Prof. 10, 15), ārum, f., = Ἀρμορικαί [ar, Celt. and old Lat., = ar, on, and mor, Celt., = mare], some of the northern provinces of Gaul, Bretagne, with a part of Normandy, Caes. B. G. 5, 53; 7, 75; Hirt. 8, 31; cf. Mann. Gall. 160.