Adjective
(mathematics) Of base four; using only four unique digits.
(music, of harmony) Having a distinct preference for intervals of fourths.
Source: en.wiktionary.orgAdorno, p. 33 The Piano Sonata is an example—the whole composition is derived from the work's opening quartal gesture and its opening phrase. Source: Internet
Hancock also developed a unique taste for "orchestral" accompaniment – using quartal harmony and Debussy -like harmonies, with stark contrasts then unheard of in jazz. Source: Internet