a bassoon larger in size and an octave lower in pitch than the ordinary bassoon; a double bassoon.
Origin of contrabassoon
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
the largest instrument in the oboe family, pitched an octave below the bassoon; double bassoon
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012