cf. generally pi 836, pi 837, pi 838, pi 842. The present entry comes from Timaeus' Platonic Lexicon (via Photius pi14 Theodoridis); this aorist infinitive is not extant anywhere in Plato, but there is a present participle, paiani/zontas, at Axiochus 365B.
Adler does print 'Paean' in upper case, but the editions of the other lexica are inconsistent in that regard; most recently Theodoridis has lower case, but in any event there is also ambiguity about whether the article immediately before it is to/n or neuter to/ (the latter to be taken with e)pikalei=sqai).