In medicine, a stoma (Greek - plr. stomata) is an opening, usually an unnatural or surgically created opening which connects a portion of the body cavity to the outside environment.

One well-known form of a stoma is a colostomy, which is a surgically-created opening in the large intestine that allows the removal of feces out of the body, bypassing the rectum, to drain into a bag or other collection device. The historical practice of trepanation was also a type of stoma.

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