The headword, evidently quoted from somewhere, is a feminine noun in the dative singular. (In the quotation given, it appears in the genitive singular.) See generally LSJ s.v. o(lkh/ III.1 (pulling, dragging, tugging towards, drawing down (of the scale), i.e. weight), and cf. omicron 174.
[1] The first gloss is another feminine noun in the dative singular (see LSJ s.v. du/namis); the second and third glosses are neuter nouns in the dative singular (see LSJ s.v. ba/ros and staqmo/n. The headword is identically glossed in the Synagoge, Photius' Lexicon (omicron225 Theodoridis), and Lexica Segueriana 316.16; cf. Hesychius omicron580, omicron582, omicron583.
[2] Aelian fr. 162 Hercher (165 Domingo-Forasté) -- reading gennikh=s from ms G (favoured by Valckenaer), not the genikh=s Adler prints.