- a bend or curve
- any cavity or hollow formed by a bending or curving
- Anat., Zool. any of various cavities, hollows, or passages; esp.,
- any of the air cavities in the skull opening into the nasal cavities
- a large channel for venous blood
- a dilated part in a blood vessel, etc.
- Bot. a rounded depression between two consecutive lobes, as of a leaf
- Med. a channel leading from a pus-filled cavity
Origin of sinusClassical Latin a bend, curve, fold
- A depression or cavity formed by a bending or curving.
- Anatomy a. A dilated channel or receptacle containing chiefly venous blood.b. Any of various air-filled cavities in the bones of the skull, especially one communicating with the nostrils.
- Medicine A fistula leading from a pus-filled cavity.
- Botany A recess or indentation between two lobes or segments, as of a leaf.
Origin of sinusMiddle English, hollow in the body, from Medieval Latin, from Latin, curve, hollow.
- (anatomy) A pouch or cavity in any organ or tissue, especially the paranasal sinus.
- (pathology) An abnormal cavity or passage such as a fistula, caused by the destruction of tissue.
From Latin sinus.