In the traditional Western pitch system, a half step is the smallest available interval. The term half step is sometimes used interchangeably with the term semitone; although the terms differ in some theoretical respects musicians generally accept either to mean the same thing. A half step can be found on the piano by locating the two most closely adjacent keys; a half step always lies between a white key and its immediately neighboring black key. This rule covers most, but not all cases: at two points on the keyboard, a half step exists between two adjacent white keys (B-C and E-F); no black key lies between them. On a fretted instrument such as a guitar, a half step lies between each adjacent fret.
Yankee Doodle in C Major.
In the “Yankee Doodle” melody above, we find one instance of a half step, occurring between the syllables on the word “Po-ny.” Another easy-to-remember example of a half step is the ominous opening to the theme of John Williams’ score for Stephen Spielberg’s Jaws. Notice the sense of urgency created by the repeated ascending two pitches in this example. In speech too, a similar rising half-step intonation of voice typically implies alarm or questioning on the part of the speaker.
Half steps are combined with whole steps to create the traditional system of major and minor scales. Indeed, the word “step” itself already implies the existence of a scale, with differently-sized steps comprising its most basic elements. The interesting case of Newton v. Diamond (2003) considers whole and half steps at some length in determining that a musical figure of three notes a half step apart is not sufficient grounds for a copyright infringement case.