What is a half step on a scale?

A half step, also known as a semitone, is the smallest interval used in Western music, representing the distance between two adjacent notes on a piano keyboard. For example, the move from C to C♯ or from E to F is a half step. It is the fundamental building block of scales and chords, contributing to the overall structure of musical harmony. In terms of frequency, a half step corresponds to a change in pitch that results from multiplying or dividing the frequency of a note by the twelfth root of two.