the word 'throttle' originates from the middle english term throtel, meaning "throat," which itself evolved from the old english þrote, also meaning "throat." this old english term is related to the old high german drozza and finds its ultimate origin in a proto-germanic root. the semantic shift from the anatomical "throat" to the action of "choking" or "strangling" is direct and literal. from this violent, physical sense, the meaning further extended metaphorically to the mechanical action of constricting or regulating the flow to an engine, giving us the modern technical usage. the logic of the word's evolution follows a clear path from a body part, to an action performed upon it, to a generalized concept of controlled constriction.

the word 'throttle' is a simplex form derived from a middle english verb. it is not productively composed of smaller, identifiable morphemes in modern english.