Depends where you are
cor in France,
corn in Romania
corn ffrengig in Welsh
corno in Italy and Mexico,
fa kuo how in Taiwan,
Franse Horing in Afrikaans,
hoorn or waldhoorn in The Netherlands,
Horn or Waldhorn in Germany,
käyrätorvi in Finland,
Keren Yaar in Hebrew,
Korno in Turkey,
Kurnu in Malta,
lesní roh in Czechoslovakia,
lesný roh in Slovak,
metsasarv in Estonia,
trompa in Spanish and Portuguese,
vadaszkürt in Hungary,
valdhorn in Denmark,
valthorn in Sweden,
valtorn in Russia,
valtorna in Lithuania
waltornia in Poland,
yuan how in Mandarin Chinese, and
yuen ho in Hong Kong Chinese.