J

Jazz: 1) an original American musical tradition rooted in performance conventions that were introduced and developed early in the 20th century by a blending of African and European musical idioms. 2) a set of attitudes and assumptions brought to music-making, chief among them the notion of performance as a fluid creative process involving improvisation; and 3) a style characterized by syncopation, cyclical formal structures and a supple rhythmic approach to phrasing known as swing. See Head.

Jubilate: A song of praise, usually based on Psalm 100.

Just Tuning: Any system of tuning in which the intervals are pure, and do not deviate from the overtone series.