noun

1. 1. the movement of an orbiting celestial object, as a star or planet, completely around another object
   2. apparent movement of the sun and stars around the earth
   3. the time taken for a body to go around an orbit and return to its original position
2. 1. a turning or spinning motion of a body, shaft, etc. around a center or axis; rotation
   2. one complete turn of such a rotating body, shaft, etc.
3. a complete cycle of events the revolution of the seasons
4. a complete or radical change of any kind a revolution in modern physics
5. overthrow of a government, form of government, or social system by those governed and usually by forceful means, with another government or system taking its place the American Revolution (1775), the French Revolution (1789), the Chinese Revolution (1911), the Russian Revolution (1917)

Etymology: ME revolucion < OFr < LL revolutio < L revolutus, pp. of revolvere: see revolve