\Rev`o*lu"tion\, n. [F. r['e]volution, L. revolutio.
See {Revolve}.]
1. 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.
2. Return to a point before occupied, or to a point
   relatively the same; a rolling back; return; as,
   revolution in an ellipse or spiral.
         That fear Comes thundering back, with dreadful
         revolution, On my defenseless head.   --Milton.
3. 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 short revolution of a day.'' --Dryden.
4. (Astron.) 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.
Note: The term is sometimes applied in astronomy to the
      motion of a single body, as a planet, about its own
      axis, but this motion is usually called rotation.
5. (Geom.) 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.
6. A total or radical change; as, a revolution in one's
   circumstances or way of living.
         The ability . . . of the great philosopher speedily
         produced a complete revolution throughout the
         department.                           --Macaulay.
7. (Politics) 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.
         The violence of revolutions is generally
         proportioned to the degree of the maladministration
         which has produced them.              --Macaulay.
Note: When used without qualifying terms, the word is often
      applied specifically, by way of eminence, to: (a) The
      English Revolution in 1689, when William of Orange and
      Mary became the reigning sovereigns, in place of James
      II. (b) The American Revolution, beginning in 1775, by
      which the English colonies, since known as the United
      States, secured their independence. (c) The revolution
      in France in 1789, commonly called the French
      Revolution, the subsequent revolutions in that country
      being designated by their dates, as the Revolution of
      1830, of 1848, etc.