The headword, evidently extracted from somewhere, is the aorist active participle, masculine nominative singular, of the verb pare/rxomai, I go by, beside; see generally LSJ s.v., and cf. pi 535 and pi 536.
[1] The gloss is the same form of the verb ei)se/rxomai, I come into, enter; see generally LSJ s.v. The headword is identically glossed in Photius' Lexicon. In Hesychius the headword and gloss participles are still aorist active, but appear in the masculine/neuter genitive plural, parelqo/ntwn and ei)selqo/ntwn respectively.