To render unconscious, as by a blow to the head.
To fall asleep, especially suddenly.
To lose the scent of hounds in fox-hunting.
To eliminate from a contest or similar.
To put to sleep.
To complete, especially in haste; knock off.
To strike or bump (someone or something) out.
To exhaust.
To cause a mechanism to become non-functional by damaging or destroying it.
To communicate (a message) by knocking.
To breathe hard, as when nearly suffocated.
To utter with breaks and interruption, in the manner of a person half suffocated.
To have the throat obstructed so as to be in danger of suffocation; to choke; to suffocate.
To control or adjust the speed of (an engine).
To cut back on the speed of (an engine, person, organization, network connection, etc.).
To strangle or choke someone.
A valve that regulates the supply of fuel-air mixture to an internal combustion engine and thus controls its speed; a similar valve that controls the air supply to an engine.
The lever or pedal that controls this valve.