A Dictionary of Music and Musicians/Concord
CONCORD is a combination of notes which requires no further combination following it or preceding it to make it satisfactory to the ear. The concords are perfect fifths, perfect fourths, major and minor thirds, and major and minor sixths, and such combinations of them, with the octave and one another, as do not entail other intervals. Thus the combination of perfect fifth with major or minor third constitutes what is known as a common chord, as (a). And different dispositions of the same notes, which are called its inversions, give, first a bass note with its third and sixth, as (b); and, secondly, a bass note with its fourth and sixth, as (c).
Besides these a chord composed of the third and sixth on the second note of any scale is regarded as a concord, though there is a diminished fifth or augmented fourth in it according to the distribution of the notes, as (d) or (e)
[ C. H. H. P. ]