1. A secret word or phrase that one uses to gain admittance or access to information.
2. Computer Science. A sequence of characters that one must input to gain access to a file, application, or computer system. Also called passkey.

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.