concussion

n [C, U] (a) injury to the brain caused by a blow, violent shaking, etc, resulting in temporary unconsciousness 脑震荡: The patient is suffering from severe concussion following a blow to the head. 患者头部受击後患严重脑震荡. (b) violent shaking or shock (caused eg by a blow, an explosion, etc) 猛烈的摇动或震动（如因撞击、 爆炸等所致）: a mighty tremor followed by minor concussions 巨大的震动及随後的轻微震荡.

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