noun. An obsolete musical instrument, probably of the clarinet class. See shawm.

noun. The lowest portion or register of the scale of the clarinet and of the basset-horn.

noun. A woodwind instrument which was the predecessor of the clarinet.

noun. The lowest range of the clarinet, reaching up to written B♭ (B flat) above middle C.

"The scale of the original instrument is still called chalumeau by the clarinet player; about the middle of the last century it was extended down to E."