chute

1. A framework, trough, or tube, upon or through which objects are made to slide from a higher to a lower level, or through which water passes to a wheel.
2. A waterfall or rapid.
3. A pen or passageway to constrain the movement of an animal, such as livestock being loaded for transport; the pen in which an animal is confined before being released in a rodeo.
4. An extension to a straightway on either the home stretch or the backstretch, to avoid having a turn at the start of the race.

Plural chutes