The Collaborative International Dictionary of English v.0.48:

Festoon \Fes*toon"\, n. [F. feston (cf. Sp. feston, It.
   festone), prob. fr. L. festum festival. See Feast.]
   1. A garland or wreath hanging in a depending curve, used in
      decoration for festivals, etc.; anything arranged in this
      way.
      [1913 Webster]

   2. (Arch. & Sculp.) A carved ornament consisting of flowers,
      and leaves, intermixed or twisted together, wound with a
      ribbon, and hanging or depending in a natural curve. See
      Illust. of Bucranium.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Festoon \Fes*toon"\, v. t. [imp. & p. p. Festooned; p. pr. &
   vb. n. Festooning.]
   To form in festoons, or to adorn with festoons.
   [1913 Webster]

WordNet (r) 3.0 (2006):

festoon
    n 1: a curtain of fabric draped and bound at intervals to form
         graceful curves
    2: an embellishment consisting of a decorative representation of
       a string of flowers suspended between two points; used on
       pottery or in architectural work
    3: flower chains suspended in curves between points as a
       decoration [syn: festoon, festoonery]
    v 1: decorate with strings of flowers; "The public buildings
         were festooned for the holiday"