= Synagoge sigma218, Photius sigma537 Theodoridis; the primary lemma and gloss also = Hesychius sigma1777, and for the secondary lemma cf. Hesychius sigma1776.
The primary headword is apparently an agent noun derived from a hypothetical verb sternotu/ptw (presumably a by-form of the more common verb sternotupe/omai). The supplementary one -- which as Theodoridis notes ought to be sternotuptou/menos (as in Suda mss GM) -- is the present middle participle, nominative singular masculine, of the same verb. Neither form (nor any other form of sternotu/ptw) is attested outside lexicography.