AAA is the chemical abbreviation for amalgama. - A, in music, is the nominal of the sixth diatonic interval of the first octave of the modern scale. It corresponds to the La of Guido. A was the lowest note of the ancient Greek scale, and for many centuries represented the deepest tone used in music. Alterations in the scale were made, however, in the 10th century by Guido, and subsequently by others, so that at present C is the first note of the natural scale, and A the sixth diatonic interval; a marks the same interval in the second octave. A is also the nominal of one of the two natural modes.