con ‧ cus ‧ sion /kənˈkʌʃ ə n/ BrE AmE noun
[ Date: 1500-1600 ; Language: Latin ; Origin: concussio , from concutere 'to shake violently' , from com- ( ⇨ COM- ) + quatere 'to shake' ]
1 . [uncountable] British English [countable] American English a small amount of damage to the brain that makes you lose consciousness or feel sick for a short time, usually caused by something hitting your head
with (a) concussion
He was rushed into hospital with concussion.
I had a concussion and a lot of scrapes and bruises.
2 . [countable usually singular] a violent shaking movement, caused by the very loud sound of something such as an explosion:
The ground shuddered and heaved with the concussion of the blast.