The Collaborative International Dictionary of English v.0.48:

Eisteddfod \Eis*tedd"fod\ ([=a]s*t[e^][th]"v[=o]d), n. [W.,
   session, fr. eistedd to sit.]
   An assembly or session of the Welsh bards; an annual congress
   of bards, minstrels and literati of Wales, -- being a
   patriotic revival of the old custom.
   [1913 Webster]

WordNet (r) 3.0 (2006):

eisteddfod
    n 1: any of several annual Welsh festivals involving artistic
         competitions (especially in singing)