A pouch or cavity in a bone or other tissue, especially one in the bones of the face or skull connecting with the nasal cavities (the paranasal sinus).
A bay of the sea; a recess in the shore.
An irregular venous or lymphatic cavity, reservoir, or dilated vessel.
Synonym of sine.
An abnormal cavity or passage such as a fistula, leading from a deep-seated infection and discharging pus to the surface.
A rounded notch or depression between two lobes or teeth in the margin of a leaf or petal.
Relating to or denoting the sinoatrial node of the heart or its function of regulating the heartbeat.
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.