Merriam-Webster Collegiate Dictionary - throttle

 I. verb  (~d; throttling)  Etymology: Middle English throtelen, from throte throat  Date: 15th century  transitive verb  1.  a.  (1) to compress the throat of ; choke  (2) to kill by such action  b. to prevent or check expression or activity of ; suppress policies that ~ creativity  2.  a. to decrease the flow of (as steam or fuel to an engine) by a valve  b. to regulate and especially to reduce the speed of (as an engine) by such means  c. to vary the thrust of (a rocket engine) during flight  intransitive verb to ~ something (as an engine) — usually used with back or down the pilot ~d back  • ~r noun  II. noun  Etymology: perhaps from Middle English *throtel, diminutive of throte throat  Date: circa 1547  1.  a. throat 1a  b. trachea 1  2.  a. a valve for regulating the supply of a fluid (as steam) to an engine; especially the valve controlling the volume of vaporized fuel charge delivered to the cylinders of an internal combustion engine  b. the lever controlling this valve  c. the condition of being ~d