Etymology From Middle English *throtel, diminutive of throte (“throat”), equivalent to throat + -le. Compare German Drossel (“throttle”). More at throat.
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:
Then up got Peg, and round the house gan scuttle, / In search of goods her customer to nail, / Until the Sultaun strain'd his princely throttle, / And hollow'd,—"Ma'am, that is not what I ail.["]1817 (date written), Walter Scott, “[Songs and Miscellanies.] Search after Happiness; or, The Quest of Sultaun Solimaun”, in The Poetical Works of Walter Scott, Esq. […], volume X, Edinburgh: […] [James Ballantyne and Company] for Arch[ibald] Constable and Co.; London: Longman, Hurst, Rees, Orme, and Brown; and John Murray, →OCLC, stanza XIX, pages 235–236:
Nor took a punch nor given a swing, / But just soaked deady round the ring / Until their brains and bloods were foul / Enough to make their throttles howl, […]1911, John Masefield, The Everlasting Mercy, London: Sidgwick & Jackson, Ltd., page 7:
1 more example
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 XXXVII, in Doctor Syn:
Etymology From Middle English throtlen (“to choke, strangle, suffocate”), from the noun (see above). Compare German erdrosseln (“to strangle, choke, throttle”).
1
To control or adjust the speed of (an engine).
2
To cut back on the speed of (an engine, person, organization, network connection, etc.).
3
To strangle or choke someone.
Grant him this, and the Parliament hath no more freedom than if it sat in his noose, which, when he pleases to draw together with one twitch of his negative, shall throttle a whole nation, to the wish of Caligula, in one neck.1649, J[ohn] Milton, ΕΙΚΟΝΟΚΛΆΣΤΗΣ [Eikonoklástēs] […], London: […] Matthew Simmons, […], →OCLC:
4
To have the throat obstructed so as to be in danger of suffocation; to choke; to suffocate.
5
To breathe hard, as when nearly suffocated.
6
To utter with breaks and interruption, in the manner of a person half suffocated.
I have seen them shiver and look pale, Make periods in the midst of sentences, Throttle their practised accent in their fears.c. 1595–1596 (date written), William Shakespeare, “A Midsommer Nights Dreame”, in Mr. William Shakespeares Comedies, Histories, & Tragedies: Published According to the True Originall Copies (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, →OCLC, [Act V, scene i]: