sinus

American  

[sahy-nuhs] / ˈsaɪ nəs /

noun

sinuses plural

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.

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sinus British  

/ 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

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sinus Scientific  

/ 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.

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Other Word Forms

• sinuslike
  adjective

Etymology

Origin of sinus

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

Explanation

A sinus infection is when the sinuses near your nose get clogged and your face aches. Good times. That’s the kind of sinus people talk about, but a sinus is any kind of space, cavity, or passage in a person's body. When you hear the word sinus, you probably think of the sinuses that can become infected if you have a bad enough cold. You might get a sinus headache when your nose is stuffed up, for example. There are many other sinuses in your body, believe it or not, from the cavernous sinus in your skull to the renal sinuses in your kidneys. The word sinus means "bend, fold, or curve" in Latin.

Example Sentences

"Shadow peaks of Sinus Iridum" by Gábor Balázs, from Hungary, took the top spot in the Our Moon category.

From BBC • Sep. 12, 2024

Peregrine will aim for the mid-latitudes’ Sinus Viscositatis, or Bay of Stickiness, named after the long-ago silica magma that formed the nearby Gruithuisen Domes.

From Seattle Times • Jan. 4, 2024

Thompson opened a second practice, Aspire Allergy & Sinus, in 2012, with a focus on sublingual drops.

From Salon • Aug. 15, 2023

A medical-minded follow-up, “Tu-Ber-Cu-Lucas and the Sinus Blues,” didn’t fare as well.

From New York Times • Feb. 20, 2023

Sinus trouble, pimples, lousy teeth, halitosis, crumby fingernails.

From "The Catcher in the Rye" by J. D. Salinger