In an organ flue pipe, the opening between the lower lip and the languet.
A pipe or duct that carries gaseous combustion products away from the point of combustion (such as a furnace).
An enclosed passageway in which to direct air or other gaseous current along.
A mouthlike opening, such as the oral cavity of a nematode.
One of the tiny pores in the epidermis of a leaf or stem through which gases and water vapor pass.
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.
An artificial anus.