concussion

impact, collision, shock, concussion mean a forceful, even violent contact between two or more things. impact may be used to imply contact between two things, at least one of which is impelled toward the other <the glass shattered on impact with the floor>. collision implies the coming together of two or more things with such force that both or all are damaged or their progress is severely impeded <the collision damaged the vehicle>. shock often denotes the effect produced by a collision and carries the suggestion of something that strikes or hits with force <the shock of falling rocks>. concussion when not in technical use, often suggests the shattering, disrupting, or weakening effects of a collision, explosion, or blow <bystanders felt the concussion of the blast>.