from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Music Of or being a medieval mode having a range from the fourth below to the fifth above its final tone.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Designating a mode lying a perfect fourth below the authentic form.
- adj. Designating a cadence in which the subdominant chord precedes the tonic.
from the GNU version of the Collaborative International Dictionary of English
- adj. Having a scale running from the dominant to its octave; -- said of certain old church modes or tunes, as opposed to those called
authentic, which ran from the tonic to its octave.
from The Century Dictionary and Cyclopedia
- In Gregorian music, noting a mode or melody in which the final is in the middle of the compass instead of at the bottom: opposed to authentic. See mode
- In modern music, noting a cadence in which the chord of the tonic is preceded by that of the subdominant. See cadence.
Medieval Latin plagālis, from plaga, plagal mode, from plagius, plagal, from Medieval Greek plagios (ēkhos), plagal (mode), from Greek, oblique, from plagos, side; see plāk-1 in Indo-European roots.(American Heritage® Dictionary of the English Language, Fourth Edition)
From Late Latin plagalis, from Latin plaga, from plagius, from Byzantine Greek πλάγιος (plagios) ‘plagal’, Ancient Greek πλάγιος (plagios, "oblique"). (Wiktionary)