How do you spell Concussion

Available Definitions:
1)  n. - A shaking or agitation; a shock; caused by the collision of two bodies.
2)  n. - A condition of lowered functional activity, without visible structural change, produced in an organ by a shock, as by fall or blow; as, a concussion of the brain.
3)  n. - The unlawful forcing of another by threats of violence to yield up something of value.