-otomy, -stomy

-otomy means incision into, and -stomy means a surgically created opening (Greek).

"OT-uh-mee / STOW-mee." Coach: "Tomy cuts into; stomy makes an opening. Do not swap them."

Examples: craniotomy, laparotomy, thoracotomy, tracheotomy, fasciotomy.

Also: colostomy, gastrostomy, ileostomy, tracheostomy, urostomy.