A harmonic progression is a sequence of numbers where the reciprocals of the terms form an arithmetic progression. In simpler terms, if you take the numbers in a harmonic progression, their inverses will be evenly spaced. For example, the sequence 1/2, 1/3, 1/4 is a harmonic progression because the reciprocals 2, 3, 4 are in arithmetic progression. Harmonic progressions are often used in mathematics and music theory. In music, they can help create pleasing melodies and harmonies. Understanding harmonic progressions can enhance one's ability to analyze and compose music, as they provide a framework for how notes relate to each other.