/huy"bawl'/ , n.
1. a drink of whiskey mixed with club soda or ginger ale and served with ice in a tall glass.
2. Railroads.
a. a signal to start a train, given with the hand or with a lamp.
b. a signal for a train to move at full speed.
3. Mil. Slang. a hand salute.
v.i.
4. Slang. to move at full speed.
v.t.
5. to signal to (the engineer of a train) to proceed.
[ 1880-85, Amer.; HIGH + BALL 1 ]