noun, plural si·nus·es.
- any of various cavities, recesses, or passages, as a hollow in a bone, or a reservoir or channel for venous blood.
- one of the hollow cavities in the skull connecting with the nasal cavities.
- an expanded area in a canal or tube.
Origin of sinus
Related formssi·nus·like, adjective
Definition for sinus (2 of 2)
Examples from the Web for sinus
A fair number explicitly ask for an antibiotic, to cover the possibility that it is “bronchitis” or a “sinus infection.”Without Education, Antibiotic Resistance Will Be Our Greatest Health Crisis|Russell Saunders|December 19, 2014|DAILY BEAST
Benign secondary headaches include headaches associated with the cold, flu, or sinus infections.
First of all, migraines often are misdiagnosed as sinus headaches.Why Everything from Frigid Temperatures to Lightning Can Induce Migraines|Caitlin Dickson|January 8, 2014|DAILY BEAST
One of the entries reads: “I spoke with a doctor for a long time about my sinus infections.”
One such case seen only at autopsy had a rupture of the aorta just above the sinus of Valsalva and died of hemopericardium.Arteriosclerosis and Hypertension:|Louis Marshall Warfield
If, however, it be normal, the gauze plug already placed between the sinus wall and the overlying bone is left undisturbed.
The aorta is not independent as in Chitons, but is a sinus like the other channels of the circulation.
This is named the sinus, and is distinguished as being angular or rounded, large or small, according to the species.A Conchological Manual|George Brettingham Sowerby
Internally the pallial line is plain, and the sinus well marked but not deep.The Sea-beach at Ebb-tide|Augusta Foote Arnold
British Dictionary definitions for sinus
noun plural -nuses
- any bodily cavity or hollow space
- a large channel for venous blood, esp between the brain and the skull
- any of the air cavities in the cranial bones