Definition of "concussion" []

• A violent jarring; a shock. See Synonyms at collision. (noun)
• An injury to an organ, especially the brain, produced by a violent blow and followed by a temporary or prolonged loss of function. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "For decades, Army award regulations used the term "concussion" for the injury, but left it to doctors or battlefield commanders to decide whether a blow to the head during combat warranted the medal."
• "Jauron had used the term concussion on Sunday to describe the injury, which Edwards suffered in the second quarter, but said that an examination will yield a better diagnosis."
• "Similarly, Girardi said he expects to add plaintiffs who have what he termed "concussion syndrome.""