1. The grasping of hands by two people, as in greeting or leave-taking.
2. Computer Science. An exchange of signals between two devices when communications begin in order to ensure synchronization.

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.