Complete Encyclopaedia of Music/A/Accord

Accord. To agree in pitch and tone. This is a French word, and is formed, according `c some authors, from the Latin ad cor; but others, with more probability, derive it from the French corde, a string or cord, on account of the agree-able unison between the sounds of two strings struck at the same time. Whence also some of the consonants in music came to be called tetrachords, hexachords, &c., which are chords of a fourth and a sixth. When two or more voices or instruments are perfectly in tune with respect to each other, and their tones blend and intermix, so as to form one consonant and harmonious result, they are said to accord. Accord is generally used as concord, and has the same meaning.

ACCORD. (noun.) Synonymous with chord; as, the accord of the sixth, &c.