外科 (wàikē) literally means 'external department' and refers to the medical specialty of surgery—the branch of medicine focused on treating injuries, diseases, or deformities through manual or instrumental procedures, especially those requiring incisions. The character 外 (wài) means 'external', reflecting surgery’s traditional distinction from internal medicine (内科, nèikē), which treats conditions without invasive techniques. 科 (kē) means 'department' or 'discipline', commonly used in academic and medical contexts to denote a specialized field.

This term is used both as a noun meaning 'surgery' and as a modifier—for example, 外科医生 (wàikē yīshēng) means 'surgeon', and 外科手术 (wàikē shǒushù) means 'surgical operation'. It appears frequently in hospital signage, medical education, health insurance forms, and patient conversations—especially when referring to treatment options, specialist referrals, or post-operative care.