1. Also called February Revolution. the uprising in Russia in March, 1917 (February Old Style), in which the Czarist government collapsed and a provisional government was established.
2. Also called October Revolution. the overthrow of this provisional government by a coup d'état on November 7, 1917 (October 25 Old Style), establishing the Soviet government.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.