1590-1600; < Medieval Latinplagālis, equivalent to plag(a) plagal mode (apparently back formation from plagius plagal; see plage) + -ālis-al1
Examples from the web for plagal
The second, fourth and second plagal tones all use the soft chromatic scale.
British Dictionary definitions for plagal
plagal
/ˈpleɪɡəl/
adjective
1.
(of a cadence) progressing from the subdominant to the tonic chord, as in the Amen of a hymn
2.
(of a mode) commencing upon the dominant of an authentic mode, but sharing the same final as the authentic mode. Plagal modes are designated by the prefix Hypo- before the name of their authentic counterparts: the Hypodorian mode
C16: from Medieval Latin plagālis, from plaga, perhaps from Greek plagos side
Word Origin and History for plagal
adj.
1590s, from Medieval Latin plagalis, from plaga "the plagal mode," probably from plagius, from Medieval Greek plagius "plagal," in classical Greek "oblique," from plagos "side" (see plagio-).