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Webster 1913 Edition
Plagal
Pla′gal
(plā′gal)
, Adj.
[F., from Gr.
πλάγιοσ
sidewise, slanting.] (Mus.)
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. Plagal cadence
, a cadence in which the final chord on the tonic is preceded by the chord on the subdominant.