stoma

noun (plural stomas or stomata /-mətə, ˌstōˈmätə/)

• any of the minute pores in the epidermis of the leaf or stem of a plant, forming a slit of variable width that allows movement of gases in and out of the intercellular spaces. Also called stomate.
• Zoology a small mouthlike opening in some lower animals.
• Medicine an artificial opening made into a hollow organ, especially one on the surface of the body leading to the gut or trachea.