surgery; surgical procedure
Refers to the medical act of operating on a patient. Often used in formal or clinical contexts.
He ended up undergoing surgery.
The success rate of surgical procedures is improving year by year.
手術 is a more general term for any operation, while 外科手術 specifically refers to surgical procedures in the field of surgery (as opposed to internal medicine).
Compound of 外科 (surgery) and 手術 (operation).