[1] Headword and gloss are alternative forms (neither of them common) of the third person singular, perfect middle/passive, of u(posto/rnumi. The headword is attested in Galen and later; the gloss occurs as early as Herodotus. Similar entries appear in Hesychius and (according to Adler) in the Ambrosian Lexicon. For the simple verb, see epsilon 3230, epsilon 3231.
[2] Perfect middle/passive infinitive of the same verb, attested twice in John Chrysostom. Bernhardy thought it should be u(pestore/sqai (a form attested in Eustathius) but Adler disagrees.