LSJ
όν, formed above, adnate, ὑδροκήλη, of encysted hydrocele, Heliod. ap. Orib. 50.31 tit. ; καλοῦσι… τοῦτο τὸ πάθος 'ἐν ἐπιγεν<ν>ητῷ (sc. χιτῶνι)' Paul.Aeg. 6.62 (in tunica superagnata vocamus, Leonid. ap. Aët. 14.22).
Liddell-Scott-Jones, Greek-English Lexicon (9th ed., 1940)