Definition of "stoma"

(botany) One of the tiny pores in the epidermis of a leaf or stem through which gases and water vapor pass.  examples

(medicine) A small opening in a membrane; a surgically constructed opening, especially one in the abdominal wall that permits the passage of waste after a colostomy or ileostomy.  examples

(zoology) A mouthlike opening, such as the oral cavity of a nematode.

An artificial anus.  examples