crankshaft
/ˈkræŋkˌʃæft/
noun
- A part of an engine that converts the up-and-down motion of the pistons into circular motion.
- A crankshaft is one of the heaviest and strongest parts of an engine.
- He learned how to balance a crankshaft in his automotive class.
- The car's crankshaft broke, and the engine had to be rebuilt.