Half step, or a half tone
A semitone, also known as a half step, is the smallest interval in Western music. It represents the distance of one step on the chromatic scale, which divides the octave into twelve equal parts. Moving one semitone up or down in pitch corresponds to moving to the adjacent key on a piano keyboard.
In terms of pitch, a semitone represents the smallest perceptible difference in pitch between two adjacent notes. For example, on a piano, the distance between any two adjacent keys, whether black or white, is a semitone. Similarly, on a guitar, moving one fret up or down corresponds to a semitone change in pitch.
The concept of a semitone is important in understanding scales, chords, and intervals in music theory. It serves as the foundation for building scales, such as the chromatic scale, which consists of all twelve semitones within an octave. It is also used to determine the distance between notes and the construction of chords, where specific combinations of semitones and larger intervals create different harmonic qualities.
The understanding and application of semitones are essential for musicians and composers to navigate and manipulate pitch in their compositions and performances. It allows for precise control over melodic and harmonic relationships, contributing to the rich and diverse musical language found in various genres and styles.