LSJ
contr. for ὀφιόεσσα (sc. νῆσος), Serpent-island, a name of Cythnos, Arist. Fr. 522; of Rhodes, Hsch. ; of an island SW. of Majorca, Str. 3.5.1; of various islands, St.Byz. s.v. Βέσβικος, al. a magical plant, Plin. HN 24.163.
Liddell-Scott-Jones, Greek-English Lexicon (9th ed., 1940)