bearing - a rotating support placed between moving parts to allow them to move easily

vane, blade - flat surface that rotates and pushes against air or water

cam - a rotating disk shaped to convert circular into linear motion

circle, round - any circular or rotating mechanism; "the machine punched out metal circles"

Ferris wheel - rotating mechanism consisting of a large upright wheel with suspended seats that remain upright as the wheel turns; provides a ride at an amusement park

gyroscope, gyro - rotating mechanism in the form of a universally mounted spinning wheel that offers resistance to turns in any direction

mechanism - device consisting of a piece of machinery; has moving parts that perform some function

rotating shaft, shaft - a revolving rod that transmits power or motion

rotor - rotating mechanism consisting of an assembly of rotating airfoils; horizontal rotors on a helicopter or compressor rotors of a jet engine