What exactly is a 'rebel yell' or a 'Bronx cheer' ?

Question

Just curious!

Answer 1

Rebel Yell - what Bo and Luke holler when they jump the General Lee over a creek.

Used during the Civil War by the southern forces, the Rebel Yell would confuse and scare Yankee troops into dropping their weapons and running away.

Bronx cheer: A raspberry (telling them to stick it)

Answer 2

Those are both really old polite terms for flatulence or farting.