The Collaborative International Dictionary of English v.0.48:

gaiety \gai"e*ty\ (g[=a]"[-e]*t[y^]), n.
   Same as Gayety.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Gayety \Gay"e*ty\, n.; pl. Gayeties. [Written also gaiety.]
   [F. gaiet['e]. See Gay, a.]
   1. The state of being gay; merriment; mirth; acts or
      entertainments prompted by, or inspiring, merry delight;
      -- used often in the plural; as, the gayeties of the
      season.
      [1913 Webster]

   2. Finery; show; as, the gayety of dress.

   Syn: Liveliness; mirth; animation; vivacity; glee;
        blithesomeness; sprightliness; jollity. See
        Liveliness.
        [1913 Webster]

WordNet (r) 3.0 (2006):

gaiety
    n 1: a gay feeling [syn: gaiety, merriment]
    2: a festive merry feeling [syn: gaiety, playfulness]