blue note
English composer
Definition
A note played at a slightly lower pitch than the standard major scale, particularly the flattened third, fifth, or seventh. Characteristic of blues and jazz tonality.
Interpretive Guidance
In Gershwin's melodies, blue notes should be rendered with a slight expressive lean — a gentle swell of tone or a tiny portamento into the note. They are not accidentals to be played straight; their expressiveness is the point.