χαιρηδών is a word that seems to have been coined by Aristophanes (Acharnians 4; Web address 1), probably on the model of its near-antonym αλγηδών (and possibly of some other similarly formed nouns, all denoting unpleasant feelings of one kind or another; see Olson 66). Dover (228) and Olson both regard the word as a hapax, but we know it was used in at least one other passage (whether by Aristophanes or someone else), since Hesychius (chi21) cites and defines it in the accusative case. The present entry is identical with a surviving scholion on Acharnians 4.