In Music theory, the diatonic major scale is a fundamental building block of the Western musical tradition. The diatonic scale is composed of two tetrachords separated by intervalss of a whole tone. The pattern of intervals in semitones is as follows 2-2-1-2-2-2-1. The major scale begins on the first note and proceeds by steps to the first octave. In solfege, the syllables for each scale degree are "Do-Re-Mi-Fa-Sol-La-Ti-Do".
The natural minor scale can be thought of in two ways, the first is as the relative minor of the major scale, beginning on the sixth degree of the scale and proceeding step by step through the same tetrachords to the first octave of the sixth degree. In solfege "La-Ti-Do-Re-Mi-Fa-Sol."
Alternately, the natural minor can be seen as a composite of two different tetrachords of the pattern 2-1-2-2-1-2-2. In solfege "Do-Re-Mi-Fa-Sol-La-Ti-Do."
All of non-folk Western harmony from the somepoint in the late Renaissance up to the late nineteenth century is based upon these two objects and the unique relationships created by this system of organizing 7 notes. It should be kept in mind that most pieces of music change key, and thus scale, but are still related to the beginning diatonic scale.
The white keys on a piano correspond to the diatonic scale of C major (C-D-E-F-G-A-B-C), with the notes a whole tone apart, except for E-F and B-C, which is an interval of a semitone (half a tone).
Diatonic comes from the greek "diatonikos" or "to stretch out". It is sometimes used to refer to all the modes, but is generally used only in reference to the major and minor scales.