The Collaborative International Dictionary
Monochord \Mon"o*chord\, n. [L. monochordon, Gr. ?, fr. ? with but one string; ? only, single + ? string: cf. F. monocorde. See Chord, and cf. Mainchord.] (Mus.) 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.
Wiktionary
n. 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.
Wikipedia
A monochord, also known as sonometer (see below), is an ancient musical and scientific laboratory instrument, involving one (mono) string (chord). The term monochord is sometimes used as the class-name for any musical stringed instrument having only one string and a stick shaped body, also known as musical bows. According to the Hornbostel–Sachs system, string bows are bar zithers (311.1) while monochords are traditionally board zithers (314). The "harmonical canon", or monochord is, at its least, "merely a string having a board under it of exactly the same length, upon which may be delineated the points at which the string must be stopped to give certain notes," allowing comparison.
In a monochord, a strings, fixed at both ends, is stretched over a sound box while one or more movable bridges are manipulated to demonstrate mathematical relationships between sound frequencies. "With its single string, movable bridge and graduated rule, the monochord (kanōn [Greek: law]) straddled the gap between notes and numbers, intervals and ratios, sense-perception and mathematical reason." However, "music, mathematics, and astronomy were [also] inexorably linked in the monochord."
Usage examples of "monochord".
Her castle was the monochord, anchored at the poles of creation, held at one end by her son and at the other by herself.
One man sang and played a monochord while a child of six or younger sang a descant beside him.
One, at least, Silence recognized as a simple monochord, used to set the Pythagorean harmonies, but the rest remained unidentifiable.
She slid down from the counter, still holding the monochord, and Isambard gave her an approving nod.
Among the heap of things, Silence could pick out another monochord, a case of tubes that probably held incense, a mirror, and a dozen other miscellaneous pieces of equipment that she could not imagine wanting for a simple transformation.
Silence reached for the monochord, searching for the correct sequence.