concussion

Từ điển WordNet v3.1 - WordNet Dictionary

noun

1. injury to the brain caused by a blow;
usually resulting in loss of consciousness (Freq. 1)
• Derivationally related forms:
concuss
• Hypernyms:
injury, accidental injury
2. any violent blow (Freq. 1)
• Derivationally related forms:
concuss
• Hypernyms:
blow, bump