Likewise or similarly in other lexica (references at Photius pi1578 Theodoridis), and cf. the scholia to Homer, Iliad 14.123, where the nominative plural of the headword occurs. (The present headword itself, in the accusative singular, is perhaps quoted from Pindar, Isthmian 4.59, where it is used of Libya, though there are other possibilities.)
On puro/s "wheat" see pi 3234.