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.
noun pl. might-have-beens
An event that could have but never did occur: “This is one of the great might-have-beens of modern history” (Arthur M. Schlesinger, Jr.)