dulcimer

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A narrow, often hourglass-shaped stringed instrument having three or four strings and a fretted fingerboard, typically held flat across the knees while sitting and played by plucking or strumming.
• noun The hammered dulcimer.

from The Century Dictionary.

• noun A musical instrument consisting of a body shaped like a trapezium, over which are stretched a number of metallic strings, having a compass—sometimes diatonic, sometimes chromatic—of from 2 to 3 octaves.
• noun A kind of woman's bonnet.

from the GNU version of the Collaborative International Dictionary of English.

• noun An instrument, having stretched metallic wires which are beaten with two light hammers held in the hands of the performer.
• noun An ancient musical instrument in use among the Jews. Dan. iii. 5. It is supposed to be the same with the psaltery.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun music A stringed instrument, with strings stretched across a sounding board, usually trapezoidal. It's played on the lap or horizontally on a table. Some have their own legs. These musical instruments are played by plucking on the strings (traditionally with a quill) or by tapping on them (in the case of the hammer dulcimers).

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a trapezoidal zither whose metal strings are struck with light hammers
• noun a stringed instrument used in American folk music; an elliptical body and a fretted fingerboard and three strings