ὄψον (opson)

1. properly, cooked meat , or, generally, meat , opposite to bread and other provisions, (Homer)
2. anything eaten with bread or food , to give it flavour and relish, κρόμυον, ποτῷ ὄψον onions, a zest or relish to wine, (Iliad by Homer); ἐσθίουσι ἐπὶ τῷ σίτῳ ὄψον (Xenophon Historicus)
3. seasoning, sauce , (Plato Philosophus); κολλύραν καὶ κόνδυλον ὄψον ἐπ᾽ αὐτῇ pudding and knuckle- sauce withal, (Aristophanes Comicus); λιμῷ ὅσαπερ ὄψῳ διαχρῆσθε, i. e. "hunger is the best sauce," (Xenophon Historicus)
4. generally, dainty fare , in plural dainties , (Plato Philosophus)
5. at Athens, mostly, fish , the chief dainty of the Athenians, (Aristophanes Comicus)
6. the fish-market , (Aristophanes Comicus) (ML)