Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio.
to distinguish (one thing from another) by contrasting
Used by arrangement with John Wiley & Sons, Inc.
The American Heritage® Dictionary of the English Language, 4th edition Copyright © 2010 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
transitive verb con·tra·dis·tin·guished, con·tra·dis·tin·guish·ing, con·tra·dis·tin·guish·es
To distinguish by contrasting qualities.