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1550s, "one who chops," agent noun from chop (v.1). Meaning "meat cleaver" is by 1818. Meaning "helicopter" is from 1951, Korean War military slang (cf. egg-beater); as a type of stripped-down motorcycle (originally prefered by Hell's Angels) from 1965.
any of several types of transistors having four semiconducting layers and therefore three p-n junctions; the thyristor is a solid-state analogue of the thyratron vacuum tube, and its name derives from the combination of the two words thyratron and transistor. A common form of thyristor is the silicon-controlled rectifier (SCR), used to convert alternating current (AC) to direct current (DC) and widely used as a component of devices that control motor speeds, liquid levels, temperatures, and pressures.