The headword is a feminine noun in the nominative/vocative singular; see generally LSJ s.v. and cf. mu 1495, sigma 333 (nominative plural), and sigma 334. The source of the entry is indeterminable, but the glossing closely follows other lexicography (see notes below). The earliest attestation of the headword form is ps.-Herodian, Partitiones 125.8.
[1] The first gloss is a neuter noun in the nominative/vocative/accusative singular; see generally LSJ s.v. The second gloss is a feminine noun in the nominative singular; see generally LSJ s.v. and kappa 2539. Identical glossing in the Synagoge and in Photius' Lexicon; cf. also e.g. Hesychius (sigma523) and the Etymologicum Gudianum (499.48).
[2] Aside from prior lexicography (n. 1), the source of this supplemental gloss is unidentifiable; cf. upsilon 698.