- hilarity (n.)
- mid-15c., from Latin hilaritatem (nominative hilaritas) "cheerfulness, gaiety, merriment," from hilaris "cheerful, merry," from Greek hilaros "cheerful, merry, joyous," related to hilaos "graceful, kindly," and possibly from a suffixed form of the PIE root *sel- (2) "happy, of good mood" (see silly). In ancient Rome, Hilaria (neuter plural of hilaris) were a class of holidays, times of pomp and rejoicing; there were public ones in honor of Cybele at the spring equinoxes as well as private ones on the day of a marriage or a son's birth.
