concussion noun definition in Injuries topic from the Oxford Advanced Learner's Dictionary

concussion

 noun: Injuries topic
(This word is only [C] in NAmE.) a temporary loss of consciousness caused by a blow to the head; the effects of a severe blow to the head such as confusion and temporary loss of physical and mental abilities (British English) He was taken to hospital with concussion. (North American English) He was taken to the hospital with a concussion. He was carried off the field with a mild concussion. She suffered mild concussion.