It is the act of modifying - change something both in a positive and negative way.
What Does The Word Alteration Mean?
The term alteration basically means the act of altering or also change, modification and adjustment.
In music alteration, usually is a very good example of chromaticism, is the application of an adjoining pitch in the chromatic scale in place of its diatonic neighbour like in an altered chord. This should not be mixed with borrowing, in which pitches or chords from equivalent key are applied as replacement for original keys.
Altered notes can be applied as leading tones to emphasis their diatonic neighbours.
In music alteration, usually is a very good example of chromaticism, is the application of an adjoining pitch in the chromatic scale in place of its diatonic neighbour like in an altered chord. This should not be mixed with borrowing, in which pitches or chords from equivalent key are applied as replacement for original keys.
Altered notes can be applied as leading tones to emphasis their diatonic neighbours.