WordNet (r) 3.0 (2006):

dada
    n 1: an informal term for a father; probably derived from baby
         talk [syn: dad, dada, daddy, pa, papa, pappa,
         pop]
    2: a nihilistic art movement (especially in painting) that
       flourished in Europe early in the 20th century; based on
       irrationality and negation of the accepted laws of beauty
       [syn: dada, dadaism]