sinus

[ sahy-nuhs ]

noun

, plural si·nus·es.

1. a curve; bend.
2. a curving part or recess.
3. Anatomy.
   1. any of various cavities, recesses, or passages, as a hollow in a bone, or a reservoir or channel for venous blood.
   2. one of the hollow cavities in the skull connecting with the nasal cavities.
   3. an expanded area in a canal or tube.
4. Pathology. a narrow passage leading to an abscess or the like.
5. Botany. a small, rounded depression between two projecting lobes, as of a leaf.

sinus

/ ˈsaɪnəs /

noun

1. anatomy
   1. any bodily cavity or hollow space
   2. a large channel for venous blood, esp between the brain and the skull
   3. any of the air cavities in the cranial bones
2. pathol a passage leading to a cavity containing pus
3. botany a small rounded notch between two lobes of a leaf, petal, etc
4. an irregularly shaped cavity

sinus

/ sī′nəs /

1. A cavity or hollow space in a bone of the skull, especially one that connects with the nose.
2. A channel for the passage of a body fluid, such as blood.

Other Words From

• sinus·like adjective

Word History and Origins

Origin of sinus¹

1590–1600; < Latin sinus (stem sinu- ) bent or curved surface, curve, fold

Word History and Origins

Origin of sinus¹

C16: from Latin: a curve, bay

Example Sentences

“Oftentimes it smells like a chemical, it smells like a bite in the air, it burns your sinuses.”

From Los Angeles Times

Stuffy sinuses with an acidic burn in the eyes.

From Los Angeles Times

He died 10 days later of cerebral venous sinus thrombosis.

From BBC

Barometric pressure sinusitis, otherwise known as barosinusitis, is an established medical condition in which people feel intense sinus headaches and inflammation.

From Los Angeles Times

A toddler who suffered sinus pain and lethargy for three months was found to have a raisin stuck up her nose.

From BBC