Which music element is defined as the 'highness' or 'lowness' of a sound?

The element defined as the 'highness' or 'lowness' of a sound is known as pitch. Pitch refers to the frequency of a sound wave, which determines how high or low a note sounds. In musical terms, higher frequencies correspond to higher pitches, while lower frequencies correspond to lower pitches. This is a fundamental aspect of music that helps to create melodies, harmonies, and overall musical structures.

Understanding pitch is essential for musicians, as it affects how notes interact with each other in a musical composition. For example, when two notes are played together, their pitches will determine whether they sound harmonious or dissonant. In contrast, volume refers to the loudness of a sound, tone refers to the quality or color of a sound, and rhythm pertains to the timing elements of music. These other elements, while important, do not specifically describe the characteristic of being 'high' or 'low' in sound.