What defines a musical interval?

A musical interval is defined as the distance between two notes, measured by the number of steps and half steps between them. This distance can be described in terms of size, such as major or minor intervals, and can have different qualities, such as perfect, augmented, or diminished.

Understanding musical intervals is fundamental to music theory, as they are essential for forming scales, chords, and harmony. The concept directly influences how melodies and harmonies are structured, allowing musicians to convey emotion and tension through the relationships between pitches.

The other choices pertain to different elements of music that, while important, do not define intervals. The quality of sound produced by an instrument relates to timbre, rhythm pertains to the timing and pacing in music, and volume refers to the loudness of sound, but none of these describe the specific relationship between two pitches as an interval does.