1. The act or process of simulating.
2. An imitation; a sham.
3. Assumption of a false appearance.
4. 1. Imitation or representation, as of a potential situation or in experimental testing.
   2. Representation of the operation or features of one process or system through the use of another: computer simulation of an in-flight emergency.

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.