1. 1. Orbital motion about a point, especially as distinguished from axial rotation: the planetary revolution about the sun.
   2. A turning or rotational motion about an axis.
   3. A single complete cycle of such orbital or axial motion.
2. The overthrow of one government and its replacement with another.
3. A sudden or momentous change in a situation: the revolution in computer technology.
4. Geology. A time of major crustal deformation, when folds and faults are formed.

[Middle English revolucioun, from Old French revolution, from Late Latin revolūtiō, revolūtiōn-, from Latin revolūtus, past participle of revolvere, to turn over. See revolve.]

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.