WordNet (r) 3.0 (2006):

maraca
    n 1: a percussion instrument consisting of a hollow gourd
         containing pebbles or beans; often played in pairs

Moby Thesaurus II by Grady Ward, 1.0:

36 Moby Thesaurus words for "maraca":
   battery, bells, bones, castanets, celesta, chime, chimes, clappers,
   crash cymbal, cymbals, finger cymbals, gamelan, glockenspiel, gong,
   handbells, idiophone, lyra, marimba, metallophone,
   orchestral bells, percussion, percussion instrument, percussions,
   percussive, rattle, rattlebones, sizzler, snappers, tam-tam,
   tintinnabula, tonitruone, triangle, tubular bells, vibes,
   vibraphone, xylophone