crankshaft
n.a long metal bar with arms that turns the power from an engine into a circular motion. It is a key part of a car's engine that helps the wheels move.
n.a long metal shaft with a series of cranks and journals, used to convert reciprocating motion into rotary motion. It is a fundamental component of internal combustion engines and steam engines.
“The mechanic replaced the worn crankshaft in the engine.”
“A damaged crankshaft can cause the engine to seize, requiring a complete engine rebuild to restore functionality.”
“Modern high-performance engines utilize forged steel crankshafts to withstand the immense torsional stresses generated by high-revving combustion cycles and heavy turbocharging.”
From crank + shaft.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.