The Collaborative International Dictionary of English v.0.48:

Glockenspiel \Glock"en*spiel`\, n. [G.; glocke bell + spiel
   play.] (Music)
   An instrument, originally a series of bells on an iron rod,
   now a set of flat metal bars, diatonically tuned, giving a
   bell-like tone when played with a mallet; a carillon.
   [Webster 1913 Suppl.]

WordNet (r) 3.0 (2006):

glockenspiel
    n 1: a percussion instrument consisting of a set of graduated
         metal bars mounted on a frame and played with small hammers
         [syn: glockenspiel, orchestral bells]

Moby Thesaurus II by Grady Ward, 1.0:

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