sinus

noun
si·​nus | \ˈsī-nəs \

Definition of sinus 

: cavity, hollow: such as

a : a narrow elongated tract extending from a focus of suppuration and serving for the discharge of pus

b(1) : a cavity in the substance of a bone of the skull that usually communicates with the nostrils and contains air

(2) : a channel for venous blood

(3) : a dilatation in a bodily canal or vessel

c : a cleft or indentation between adjoining lobes (as of a leaf or corolla)

Examples of sinus in a Sentence

Recent Examples on the Web

Then head to your doctor, as bad breath could be a symptom of various medical conditions such as sinus or lung infections, bronchitis, gastric reflux, a tonsil infection, and even some liver or kidney diseases. Samantha Lefave, Redbook, "Why You Should Never Ignore Sweet-Smelling Urine (or These Other Body Odors)," 3 Aug. 2018 Viral sinus infections—also known as sinusitis—usually clear up on their own, says Dr. Lebowitz. Amanda Macmillan, Health.com, "A 13-Year-Old Died After a Sinus Infection Traveled to His Brain. How Does That Happen?," 16 Mar. 2018 Dehydration also makes mucus in the nose, throat and lungs dry up, which can then clog sinuses and respiratory tubes. Mark Fischetti, Scientific American, "Fact or Fiction?: Feed a Cold, Starve a Fever," 3 Jan. 2014 This has revealed the brain, the sense organs, sinuses, blood vessels, and nerves that are hidden inside the skull of T. rex. Robert Clark, National Geographic, "Why Today is the Golden Age for Dinosaur Discoveries," 2 June 2018 This eBook provides information about seasonal (sinus), food, skin, asthma, and insect sting allergies. Indianapolis Star, "Free eBook: Overcoming Allergies," 7 May 2018 The results indicated that the source of Mimi's problems was not her ears or her sinuses, but rather her lungs. Sandra G. Boodman, chicagotribune.com, "The girl who couldn't stop coughing," 5 Apr. 2018 The results indicated that the source of Mimi’s problems was not her ears or her sinuses, but rather her lungs. Sandra G. Boodman, Washington Post, "Why did a little girl have a persistent ‘smoker’s cough’?," 31 Mar. 2018 Each sinus has an opening that connects it to your nose. Korin Miller, SELF, "A 13-Year-Old Boy Died After a Sinus Infection Spread to His Brain," 29 Mar. 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'sinus.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of sinus

15th century, in the meaning defined above

History and Etymology for sinus

Middle English, from Medieval Latin, from Latin, curve, fold, hollow

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Statistics for sinus

Last Updated

10 Dec 2018

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Time Traveler for sinus

The first known use of sinus was in the 15th century

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More Definitions for sinus

sinus

noun

English Language Learners Definition of sinus

: any of several spaces in the skull that connect with the nostrils

sinus

noun
si·​nus | \ˈsī-nəs \

Kids Definition of sinus

: any of several spaces in the skull mostly connected with the nostrils

sinus

noun
si·​nus | \ˈsī-nəs \

Medical Definition of sinus 

: a cavity or hollow in the body: as

a : a narrow elongated tract extending from a focus of suppuration and serving for the discharge of pus a tuberculous sinus

b(1) : a cavity in the substance of a bone of the skull that usually communicates with the nostrils and contains air

(2) : a channel for venous blood

(3) : a dilatation in a bodily canal or vessel

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More from Merriam-Webster on sinus

Rhyming Dictionary: Words that rhyme with sinus

Spanish Central: Translation of sinus

Nglish: Translation of sinus for Spanish Speakers

Britannica.com: Encyclopedia article about sinus

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