The headword is the genitive singular of plei/wn, the comparative of polu/s "much". The comparative used as the gloss occurs at Odyssey 11.359, in the feminine dative singular with the sense "fuller," i.e. as a comparative of ple/ws. In later writers, pleio/teros can be used as a comparative of polu/s. The masculine/neuter genitive singular is not attested in extant texts, but it may have occurred in an ambiguous passage. For polu/s and ple/ws, cf. pi 1717 and pi 1718.
Adler reports different glossing in the Ambrosian Lexicon (791), repeated in Eustathius' Commentary on the Iliad.