con·cus·sion 
/kənˈkʌʃən/ noun
plural con·cus·sions /kənˈkʌʃən/ noun : an injury to the brain that is caused by something hitting the head very hard [count] (US)
▪ She suffered a severe concussion after falling on the ice. [noncount] (Brit) ▪ He went to hospital with concussion.
▪ She suffered a severe concussion after falling on the ice. [noncount] (Brit) ▪ He went to hospital with concussion.
