concussion
n. countable B2 Upper Intermediate US //kənˈkəʃən// UK //kənkˈʌʃən// con·cus·sion
n. a head injury caused by a hard blow to the head, often making you feel dizzy or confused.
n. a traumatic brain injury resulting from a blow to the head, characterized by temporary disruption of neurological function.
He suffered a concussion after falling off his bike.
The doctor told him to rest for a week because of the concussion.
Concussions are invisible injuries that require careful monitoring to ensure the brain heals properly before returning to sport.
From Latin concussiō. Equivalent to concuss + -ion.