'Dulcimer' definitions:

Definition of 'dulcimer'

noun

A stringed instrument used in American folk music; an elliptical body and a fretted fingerboard and three strings

noun

A trapezoidal zither whose metal strings are struck with light hammers

From: GCIDE

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. [1913 Webster]

Dulcimer (Heb. sumphoniah), a musical instrument mentioned in Dan. 3:5, 15, along with other instruments there named, as sounded before the golden image. It was not a Jewish instrument. In the margin of the Revised Version it is styled the "bag-pipe." Luther translated it "lute," and Grotius the "crooked trumpet." It is probable that it was introduced into Babylon by some Greek or Western-Asiatic musician. Some Rabbinical commentators render it by "organ," the well-known instrument composed of a series of pipes, others by "lyre." The most probable interpretation is that it was a bag-pipe similar to the zampagna of Southern Europe.