axle
- A rod or spindle (either fixed or rotating) passing through the center of a wheel or group of wheels. nounThe car's axle was damaged in the accident, making it difficult to drive.The mechanic inspected the axle to ensure it was properly aligned.
- The central shaft for a rotating wheel or gear, which can be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. nounThe bicycle's axle needed lubrication to reduce friction.The engineer designed a new type of axle to improve vehicle performance.