'bisdiapason' definitions:

Definition of 'bisdiapason'

From: GCIDE

Disdiapason \Dis*di`a*pa"son\, n. [Pref. dis- (Gr. ?) + diapason.] (Anc. Mus.) An interval of two octaves, or a fifteenth; -- called also bisdiapason. Compare diapason[1]. [1913 Webster]