|Origin:||concussio, from concutere 'to shake violently', from com- ( COM-) + quatere 'to shake'|
1MI [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.