Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio.
a personality type characterized by serenity, relaxation, amiability, etc., traits thought to make one less susceptible to heart attacks
Origin: see Type A
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.
or Type Badjective
Of or relating to a behavior pattern marked by a relaxed manner, patience, and friendliness that possibly decreases one's risk of heart disease.noun
One who exhibits this behavior pattern.