Bible Dictionaries
Plagal

Webster's Dictionary

(a.) 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.

Bibliography Information
Webster, Noah. Entry for 'Plagal'. Noah Webster's American Dictionary. https://www.studylight.org/​dictionaries/​eng/​web/​p/plagal.html. 1828.