FUSEE

noun Etymology: French fusée, literally, spindleful of yarn, from Old French, from fus spindle, from Latin fusus Date: 1622 a conical spirally grooved pulley in a timepiece from which a cord or chain unwinds onto a cylinder containing the mainspring and which by its increasing diameter compensates for the lessening power of the spring, a red signal flare used especially for protecting stalled trains and trucks