Emily Dickinson Lexicon

HI-LAR'I-TY, n. [L. hilaritas; Gr. ιλαρος, joyful, merry. If r is radical, this cannot be from ιλαω, to be propitious.]

Mirth; merriment; gayety. Hilarity differs from joy; the latter, excited by good news or prosperity, is an affection of the mind; the former, by social pleasure, drinking, &c. which rouse the animal spirits.