What does the word diapason mean?

Usage examples for diapason

  1. The words- the inspiring words of the labor chant had caught the people on the sidewalk, and a great diapason was rising: March on! – In the Heart of a Fool by William Allen White
  2. At the great stone basin Malcolm set the swan spouting, but the sweet musical jargon of the falling water seemed almost coarse in the soundless diapason of the moonlight. – The Marquis of Lossie by George MacDonald