Source : Webster's Revised Unabridged Dictionary (1913)

Dulcimer \Dul"ci*mer\, n. [It. dolcemele,r Sp. dulcemele, fr. L.
   dulcis sweet + melos song, melody, Gr. ?; cf. OF. doulcemele.
   See {Dulcet}, and {Melody}.] (Mus.)
   (a) An instrument, having stretched metallic wires which are
       beaten with two light hammers held in the hands of the
       performer.
   (b) An ancient musical instrument in use among the Jews.
       --Dan. iii. 5. It is supposed to be the same with the
       psaltery.

Source : WordNet®

dulcimer
     n 1: a stringed instrument used in American folk music; an
          elliptical body and a fretted fingerboard and three
          strings
     2: a trapezoidal zither whose metal strings are struck with
        light hammers