n. The branch of medicine that deals with the diagnosis and treatment of injury, deformity, and disease by manual and instrumental means.n. A surgical operation or procedure, especially one involving the removal or replacement of a diseased organ or tissue.n. An operating room or a laboratory of a surgeon or of a hospital's surgical staff.n. The skill or work of a surgeon.n. Chiefly British A physician's, dentist's, or veterinarian's office.n. Chiefly British The period during which a physician, dentist, or veterinarian consults with or treats patients in the office.