Source : Webster's Revised Unabridged Dictionary (1913)

Conviviality \Con*viv`i*al"i*ty\, n.; pl. {Convivialities}.
   The good humor or mirth indulged in upon festive occasions; a
   convivial spirit or humor; festivity.

Source : WordNet®

conviviality
     n 1: a jovial nature [syn: {joviality}]
     2: a boisterous celebration; a merry festivity [syn: {merrymaking},
         {jollification}]