ˌɒpəˈɹeɪʃən ˌɑpəˈɹeɪʃən ˈsɝdʒəɹi ˈsɜːdʒəɹi a medical procedure involving an incision with instruments; performed to repair damage or arrest disease in a living body they will schedule the operation as soon as an operating room is available he died while undergoing surgery a room in a hospital equipped for the performance of surgical operations great care is taken to keep the operating rooms aseptic a room where a doctor or dentist can be consulted he read the warning in the doctor's surgery the branch of medical science that treats disease or injury by operative procedures he is professor of surgery at the Harvard Medical School