monochord

An acoustic instrument consisting of a sounding box with one string and a movable bridge, used to study musical tones.

An acoustical instrument, invented at a very early date in Egypt or Greece, consisting of a long resonance-box over which a single string of gut or wire is stretched, the vibrating length, and thus the pitch, of which is fixed by a movable bridge.

An instrument for experimenting upon the mathematical relations of musical sounds. It consists of a single string stretched between two bridges, one or both of which are movable, and which stand upon a graduated rule for the purpose of readily changing and measuring the length of the part of the string between them.

A musical instrument for experimenting with the mathematical relations of musical sounds, consisting of a single string stretched between two bridges, one or both of which can be moved, and which stand upon a graduated rule for the purpose of changing and measuring the length of the part of the string between them.