1. A violent jarring; a shock: The concussion from the explosion broke windows three blocks away.
2. An injury to an organ, especially the brain, produced by a violent blow and followed by a temporary or prolonged loss of function.
[Middle English concussioun, bruise, contusion, from Latin concussiō, concussiōn-, concussion, from concussus, past participle of concutere, to strike together; see concuss.]
con·cus′sive (-kŭs′ĭv) adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.