chalumeau
Concise Oxford English Dictionary © 2008 Oxford University Press:
chalumeau /ˈʃalʊməʊ/
▶noun (pl. chalumeaux pronunc. same)
- 1 a reed instrument of the early 18th century from which the clarinet was developed.
- 2 (also chalumeau register) the lowest octave of the clarinet's range.
– origin C18: from Fr., from L. calamellus ‘little reed’.
'chalumeau' also found in these Oxford entries:

