Lewis & Short

obsōnĭum or ops-, ii, n., = ὀψώνιον, that which is eaten with bread; victuals, viands, esp. fish: tu facito obsonatum nobis sit opulentum obsonium, Plaut. Bacch. 1, 1, 64: curare, id. Merc. 3, 3, 22: obsonare, id. Stich. 3, 1, 36: scindere, Sen. Vit. Beat. 17, 2; Plin. 31, 7, 41, § 87: coëmere, Hor. S. 1, 2, 9: opsonia rancidula, Juv. 11, 134.
Also of fruit, Plin. 15, 19, 21, § 82.