causality paradox definition by American Heritage Dictionary
nounThe 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.
A hypothetical effect that would result if an individual were to travel back in time and cause changes to the circumstances that led to his or her current actions.
causality paradox - Science Definition
A paradox resulting from hypothetical time travel, in which an individual travels back in time and performs actions that would ultimately have made the time travel impossible (as by killing one's parents at a time preceding one's birth).