An avoid note is a note in a jazz scale that is considered, in jazz theory and practice, too dissonant to be played against the underlying chord, and so is either avoided or chromatically altered. For example, in major-key harmony the 4th, and thus the 11th, is an avoid note and is therefore either treated as a passing tone or is augmented (raised a semitone). Avoid notes are often a minor second (or a minor ninth) above a chord tone or a perfect fourth above the root of the chord.