The diatonic scale consists of 5
whole tones and
2
semitones (S). Scales played on the white keys
of a piano keyboard are diatonic. The diatonic scale is also know as "church mode" or "ecclesiastical mode". The church modes are used in Gregorian chant and in pre-baroque early
music but also to some extent in newer jazz music.
From the beginning of the 17th century the scales used in European
compositional music are primarily the major and the minor scales. In the
harmonic minor scale type an augmented second (A) occurs between the 6th and
7th tone.
Music Dictionary