The headword is a masculine noun equated by LSJ s.v. with psi 136. The entry as a whole -- unparalleled in other lexica -- is classified by Adler as 'gl. Od.' (and ascribed by her to the source of the Ambrosian Lexicon). This presumably refers to Homer, Odyssey 15.312 and/or and/or 17.12 and/or 17.362, where the related neuter noun pu/rnon ('wheaten bread': LSJ) occurs. There is nothing relevant in the scholia to those passages, but see generally Athenaeus, Deipnosophists 3.114D (3.81 Kaibel).