From Middle English throtelen 'to strangle,' derived from throte 'throat' — the mechanical throttle was named for its action of choking or restricting airflow, just as hands throttle a windpipe.
A device controlling the flow of fuel or air to an engine; also, the throat or windpipe (archaic).
From Middle English throtelen 'to strangle,' a frequentative form derived from throte 'throat' (from Old English throtu 'throat'). The original meaning was the throat itself, then to choke or strangle by compressing the throat. The mechanical sense (a valve controlling engine airflow) emerged in the 19th century by analogy — a throttle valve chokes or restricts the flow of air to an engine, just as a hand throttles a throat. Key roots: *trud- (Proto-Germanic: "throat, to swell").
The mechanical throttle was named by direct metaphor from the body: just as throttling a person chokes their airway, a throttle valve chokes the airflow to an engine. The same metaphor produced 'choke' as an alternative name for the device that restricts the air-fuel mixture in a carburetor.