the act of revolving, or turning round on an axis or a center; the motion of a body round a fixed point or line; rotation; as, the revolution of a wheel, of a top, of the earth on its axis, etc.-return to a point before occupied, or to a point relatively the same; a rolling back; return; as, revolution in an ellipse or spiral.-the space measured by the regular return of a revolving body; the period made by the regular recurrence of a measure of time, or by a succession of similar events.-the motion of any body, as a planet or satellite, in a curved line or orbit, until it returns to the same point again, or to a point relatively the same; -- designated as the annual, anomalistic, nodical, sidereal, or tropical revolution, according as the point of return or completion has a fixed relation to the year, the anomaly, the nodes, the stars, or the tropics; as, the revolution of the earth about the sun; the revolution of the moon about the earth.-the motion of a point, line, or surface about a point or line as its center or axis, in such a manner that a moving point generates a curve, a moving line a surface (called a surface of revolution), and a moving surface a solid (called a solid of revolution); as, the revolution of a right-angled triangle about one of its sides generates a cone; the revolution of a semicircle about the diameter generates a sphere.-a total or radical change; as, a revolution in one's circumstances or way of living.-a fundamental change in political organization, or in a government or constitution; the overthrow or renunciation of one government, and the substitution of another, by the governed.