A step is the difference in pitch between two consecutive notes in a scale, or, alternatively, it is the interval between any two consecutive scale degrees. Any larger interval is called a skip.
Steps are classified as either half steps or whole steps. A whole step (also called a whole tone) consists of two half steps. In Western music, an octave is divided into twelve tones or half steps, and a scale contains seven of these. Thus, some of the distances between adjacent notes in a scale span a half step and some span a whole step.