DIATONIC scale: a scale having eight notes to the octave, like the major or minor scales
MODE: the choice of a diatonic scale, usually major or minor,
but with other possibilities in folk music
The opening theme of Movement III of Bartók's Sonata for
Two Pianos and Percussion uses an unusual folk mode.
TONAL: having a home key or tonic, that is, a single note which
is the focal point or resting place [noun: TONALITY]
Bartók's music is generally tonal (though not obviously so), unlike Schoenberg's,
which is generally atonal.
CHROMATIC: the opposite of DIATONIC, using all 12 notes
Bartók's melodies tend to be modal, but his harmonies
tend to be chromatic.