A musical interval is the distance between two pitches, measured in terms of the number of steps between them. Intervals can be described as whole steps or half steps, and they are fundamental in creating melodies and harmonies. Common intervals include the major third, perfect fifth, and octave, each contributing to the overall sound and emotion of a piece of music. Intervals are categorized into two main types: melodic intervals, which occur when notes are played in sequence, and harmonic intervals, where notes are played simultaneously. Understanding intervals is essential for musicians, as they form the basis for scales, chords, and musical composition.