Revolution
a fundamental change in government, or in the political constitution of a country, effected suddenly and violently, and mainly brought about by internal causes; a revolt against the constituted authority successfully and completely accomplished. In most revolutions there are three turns of the wheel. First there is a moderate movement forward, then, after a time, a second forward movement. The extreme party who now come into power create a reaction against the revolution, and the wheel moves backward. In the great French Revolution first there were the Girondists, then the Jacobins, then the reaction to monarchy under the first Napoleon, and in due time again to the Bourbons. In the United States the term Revolution is applied specifically to the American War for Independence, which began in 1775 with the irregular running fight popularly known as the battle of Lexington, and practically ended with the surrender of Lord Cornwallis, at Yorktown, Va., to the combined forces of the French and Americans, in the year 1781. The English Revolution was that revolution in England by which James II. was driven from the throne in 1688. The Russian Revolution was that of 1917 which led to the triumph of the Bolsheviki over the moderates, and the development of Soviet power. The German Revolution was that of 1918, by which the German Emperor and the kings and other reigning princes of the various sovereign German states were driven from their thrones.
In astronomy: (1) The motion of a planet around the sun, or of a satellite around a planet. The point to which it REVOLUTIONARY CALENDAR returns is called annual, anomalistic, nodical, sidereal, or tropical, according as it has a relation to the year, the anomaly, the nodes, the stars, or the tropics. (2) See ROTATION. In geometry, when one line moves about a straight line, called the axis, in such a manner that every point of the moving ng line generates a circumference of a circle, whose plane is perpendicular to the axis, that motion is called revolution, and the surface is called the surface of revolution. Every plane through the axis is called a meridian plane, and the section which this plane cuts from the surface is called a meridian curve. Every surface of revolution can be generated by revolving one of its meridian curves about the axis. The revolution of an ellipse round its axis generates an ellipsoid; the revolution of a semicircle round the diameter generates a sphere; such solids are called solids of revolution.