The (substantively unglossed) headword is the epic perfect participle of sunoxo/w, nominative dual; it occurs in Homer, Iliad 2.218, describing the shoulders of the ugly Thersites (theta 257) 'having bent together on his chest'. [Mss AG, Adler reports, read sunwxoko/te, which would not fit the meter.] Hesychius sigma2675 has sunokwxo/te, relating it to the noun sunokwxh/ (from the verb sune/xw).
The substantive glossing absent here is provided by the scholia to the passage, and Etymologicum Magnum 735.46-53.