Lewis & Short

săgŭlum, i, n. dim. [sagum], a small military cloak (usually the purple-colored one of the general), * Cic. Pis. 23, 55; Caes. B. G. 5, 42; Liv. 7, 34 fin.; 21, 4; 27, 19 fin.; 30, 17; Tac. H. 2, 20; 5, 23; id. G. 6; Verg. A. 8, 660; Sil. 4, 519; 17, 532; Suet. Vit. 11.