throttle

Etymology 1

From Middle English *throtel, diminutive of throte (“throat”), equivalent to throat + -le. Compare German Drossel (“throttle”). More at throat.

noun

1. 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.
2. The lever or pedal that controls this valve.
   To my unpractised eye, the undulations in the track were quite imperceptible, but the engineer's hand on the throttle was never still. 1961 July, J. Geoffrey Todd, “Impressions of railroading in the United States: Part Two”, in Trains Illustrated, page 425
3. (anatomy, archaic) The windpipe or trachea.
   From the cabin came that horrible song: "Here's to the feet wot have walked the plank. ⁠Yo ho! for the dead man's throttle." 1915, Russell Thorndike, chapter //dummy.host/index.php?title=s%3Aen%3ADoctor+Syn%2FChapter+37 XXXVII, in Doctor Syn

Etymology 2

From Middle English throtlen (“to choke, strangle, suffocate”), from the noun (see above). Compare German erdrosseln (“to strangle, choke, throttle”).

verb

1. (transitive) To control or adjust the speed of (an engine).
2. (transitive) To cut back on the speed of (an engine, person, organization, network connection, etc.).
3. (transitive) To strangle or choke someone.
4. (intransitive) To have the throat obstructed so as to be in danger of suffocation; to choke; to suffocate.
5. (intransitive) To breathe hard, as when nearly suffocated.
6. (transitive) To utter with breaks and interruption, in the manner of a person half suffocated.