The headword is a masculine noun in the nominative singular. See LSJ s.v. ou)do/s (A); cf. omicron 827, chi 193 gloss. (For B, see omicron 46.)
[1] For flia/ see phi 536. Although its primary meaning is "doorpost," it seems to be used here in the sense of "support" (see LSJ s.v., 4), or even, more broadly, "lintel" (LSJ s.v., 2).
[2] The headword is identically glossed in the Synagoge and Photius' Lexicon (omicron623 Theodoridis); cf. Hesychius omicron1593; Lexica Segueriana 322.1; Erotian 25.9 (Klein, p. 54.19); a scholion to Homer, Iliad 6.375 (web address 1), where the headword appears in the accusative singular, ou)do/n; and Apion s.v. ou)do/n. Adler also cites the Lexicon de Spiritu, L.C. Valckenaer, ed.