Etymology: counter-prefix 2k.Previous versions of the OED give the stress as: ˈcounter-diaˌpason.
Music.
An organ stop an octave lower in pitch than the ordinary diapason.
ΚΠ
1852 tr. J. J. Seidel Organ & its Constr. 94 Large organs have sometimes, in the great organ, both a diapason eight feet and one sixteen feet, the latter being then called double-diapason, or counter-diapason.
This entry has not yet been fully updated (first published 1893; most recently modified version published online September 2020).