[1] The headword is present infinitive of potnia/omai, from po/tnia (pi 2138): thus, literally, to cry aloud (in horror or indignation) 'o mistress'; attested only in later Greek prose, see LSJ s.v. No precise equivalent for the glossing in other lexica, but Etymologicum Magnum 685.52 is very close.
[2] Same or similar glossing in other lexica, and a scholion on Lucian (167.1 Rabe). Evidently quoted from somewhere.
[3] (Again it must be quoted from somewhere; there are numerous possibilities.) Moeris asserts that potniw/menos is Attic corresponding to common Greek dusforw=n.