CHORD, in Music, is sometimes used synonymously with Consonance, to denote the combined effect of two musical sounds heard together, but more commonly practical musicians and theorists intend three sounds, at least, to be heard together, to constitute a chord ; and these they distinguish by various names, as accidental, borrowed, common, complete, connecting, direct, equi vocal, essential, uncommon, &c. or, the added sixth, diminished seventh, extreme sharp sixth, fifth and sixth, fourth and sixth, redundant sixth, second and fourth, second and third, sixth, sixth and ninth, sixth and se venth, third and fourth, &c. It is almost general with writers on the theory cf music, to use only the Arabic numerals to express chords. Thus the common chord 8 3 5 they denote by 5 or 8 or 3, &c. and when sharps or flats 3 5 8 occur annexed to these, in figuring thorough-bass, these last generally have reference to the sharps or flats affix ed to the beginning of the piece or stave, usually called its signature ; but they are not in the habit of distinguish ing the major from the minor intervals, that enter into the composition of chords, by particular marks, though the same is often much wanted. The Rev. Henry Lis
ton, in his Essay on Perfect Intonation, p. 50, has in some degree remedied this defect, by the use of the Ara bic numerals, 2, 3, 4, 5, 6, 7, and 8, for the minor in tervals of these names, and the Roman numerals, I, II, III, IV, V, VI, VII, and VIII, for the major intervals ; by the use of b, affixed to these Arabic numerals, to denote the depression or lessening of a minor interval, either a medium or a minor semitone, 3 or S (see our Table of Intervals, Plate XXX. in Vol. II.;) by adding t; to the Roman numerals, to denote the elevation or enlarging of a a major interval, by 3 or S, according to their places in the scale ; and by using also the grave and acute marks,' and', affixed likewise to the numerals, to denote the depression or elevation of a major comma C. Thus the chord call VI 6 ed the common chord is III or or , the oc tave being here understood. The chord of diminished