The headword noun is feminine, here in the nominative (and vocative) singular; cf. LSJ s.v. It appears in the dative singular at Homer, Odyssey 5.337 (web address 1), where the daughter of Cadmus (OCD(4) s.v., kappa 21, kappa 22, kappa 23) Ino (OCD(4) s.v. Ino-Leucothea, iota 381, iota 382, iota 386, kappa 242, lambda 331, and omega 12), now a sea-nymph, rises up in flight to appear before Odysseus on his raft.
[1] The gloss is a feminine substantive, given here in the nominative singular; see LSJ s.v. Same glossing at Etymologicum Magnum 685.11; cf. Hesychius s.v. and the scholia to Homer, Odyssey 5.337 (above). Adler also cites the Ambrosian Lexicon (1006).