What is an 'interval' in music theory?

In music theory, an 'interval' refers specifically to the distance between two notes, which is measured in terms of pitch. This distance can be quantified by counting the number of steps, or scale degrees, between the two notes, including both the starting and ending notes. Intervals can be classified into various types, such as major, minor, perfect, diminished, and augmented, depending on their size (the number of half steps they encompass) and their specific qualities.

Understanding intervals is essential for musicians as they form the basis of melodies and harmonies, and influence the overall sound and character of a piece. Recognizing how different intervals evoke various feelings or tensions is a fundamental skill in music composition and performance.

The other options relate to different aspects of music but do not describe intervals. Rhythm pertains to the timing of notes, volume refers to dynamics in sound, and emotional tone involves subjective interpretations of a musical piece, none of which accurately define what an interval is in the context of music theory.