Lewis & Short

magmentum, i, n. [contr. from magimentum, from root mag; cf. mactare and mactus].
In relig. lang., that which magnifies or glorifies, an offering, sacrifice, Inscr. Orell. 2489; 2490; Inscr. Grut. 23, 12; 229, 1; Arn. 7, 24; cf. in preced., Varr. L. L. 5, § 112 Müll.