X-otomy means to cut X. Tomos = cut. Craniotomy means to cut open the skull. It's implied that the cut piece will be put back in place afterwards. X-ectomy mea

X-otomy means to cut X. Tomos = cut. Craniotomy means to cut open the skull. It's implied that the cut piece will be put back in place afterwards. X-ectomy means to cut X out. Ecto = out, tomos = cut. Appendectomy = cut out appendix. It's surgically removed from the patient, permanently. X-ostomy means to cut open a hole in X. Stoma = hole/mouth, tomos = cut. Colostomy = cut open a hole in the colon. There's an implication that the hole will be there in the long term. Bonus: XY anastomosis. Open X into Y, connecting them together. Ana = on/upon, stoma = hole/mouth. Ileoanal anastomosis means opening the ileum into the anus, bypassing the colon and rectum. X and Y are implied to have a lumen and the contents of X are implied to flow into Y. Lumen = light, it means a cavity, the interior space of a body structure, such as a blood vessel.