The headword is the epic/Ionic present active participle, feminine nominative (and vocative) singular, of the verb pra/ssw/pra/ttw, I perform, practice, achieve, accomplish; see generally LSJ s.v.
The entry seems to have been generated from Homer, Iliad 1.483 (web address 1), for the scholia to which, see next note. The Homeric text uses the compound diaprh/ssousa (passing over, making way) to describe the Achaean ship making its way back to the Greek camp from the island of Tenedos, after Odysseus has delivered Chryseis to her father.
[1] The gloss is the same form as the headword, but from the contract verb diapera/w, I go over, traverse; see generally LSJ s.v. A scholion to the aforementioned Homeric passage provides the same gloss. The lemma is transmitted as prh/sousa by ps.-Zonaras 1586.4 and by Lexicon Ambrosianum 1342 and ms V (so Adler), but the gloss is identical.