sinus

Plural: sinuses

Noun

• A cavity or hollow space, especially in the skull bones.
• an abnormal passage leading from a suppurating cavity to the body surface
• any of various air-filled cavities especially in the bones of the skull
• a wide channel containing blood; does not have the coating of an ordinary blood vessel
• 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).
• An irregular venous or lymphatic cavity, reservoir, or dilated vessel.
• An irregular venous or lymphatic cavity, reservoir, or dilated vessel.
• Relating to or denoting the sinoatrial node of the heart or its function of regulating the heartbeat.
• 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.
• A bay of the sea; a recess in the shore.
• Synonym of sine.

Examples

• Thinking too hard about complex word plays can give you a sinus headache.

Synonyms

fistula, venous sinus, sine