cymbal

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

• noun A percussion instrument consisting of a concave brass plate that makes a loud clashing tone when hit with a drumstick or when used in pairs.

from The Century Dictionary.

• noun One of a pair of concave plates of brass or bronze which, when struck together, produce a sharp, ringing sound: usually in the plural.
• noun In organ-building, a mixture-stop of very high pitch.
• noun A musical instrument made of a piece of steel wire, in a triangular form, on which are passed several rings, which are touched and shifted along the triangle with an iron rod held in the right hand, while the cymbal is supported in the left by a cord. Also spelled symbal. Imp. Dict.

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

• noun A musical instrument used by the ancients. It is supposed to have been similar to the modern kettle drum, though perhaps smaller.
• noun A musical instrument of brass, shaped like a circular dish or a flat plate, with a handle at the back; -- used in pairs to produce a sharp ringing sound by clashing them together.
• noun A musical instrument used by gypsies and others, made of steel wire, in a triangular form, on which are movable rings.

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

• noun music a concave plate of brass or bronze that produces a sharp, ringing sound when struck: played either in pairs, by striking them together, or singly by striking with a drumstick or the like.

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

• noun a percussion instrument consisting of a concave brass disk; makes a loud crashing sound when hit with a drumstick or when two are struck together