alphorn
Multiple Entries:alphorn alpenhorn
Concise Oxford English Dictionary © 2008 Oxford University Press:
alphorn /ˈalphɔːn/
▶noun another term for alpenhorn.
Concise Oxford English Dictionary © 2008 Oxford University Press:
alpenhorn /ˈalpənhɔːn/ (also alphorn)
▶noun a very long valveless wooden wind instrument played like a horn and used for signalling in the Alps.
– origin C19: from Ger., lit. ‘Alp horn’.
'alphorn' also found in these Oxford entries:

