The headword, a neuter noun which can literally mean any small dish of cooked food, is a diminutive of o)/yon (omicron 1069, omicron 1087); and the entry as a whole occurs in the Lexicon de spiritu, from a comment on Gospel of John 21.9, where this word is used (web address 1).
In modern Greek, ya/ri has come to mean (cooked) "fish."