sinus

noun
si·​nus | \ ˈsī-nəs How to pronounce sinus (audio) \

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

But occasionally, infections can occur in a region called the sphenoid sinus, located behind the eyes near the optic nerve. Amanda Macmillan, Health.com, "A 13-Year-Old Died After a Sinus Infection Traveled to His Brain. How Does That Happen?," 16 Mar. 2018 The handmade, calming piece will de-puff skin when laid over the eye area, while the cooling sensation may even alleviate stress and sinus pressure. Jenna Rennert, Vogue, "10 Holiday Gifts for the Skin Care–Obsessed Best Friend in Your life," 12 Nov. 2018 According to the report, the bullet tore through her forehead, nose, sinuses, jaw bones and badly damaged her eyes. Alexandria Hein, Fox News, "Face transplant gives woman 'second chance' 3 years after suicide attempt," 14 Aug. 2018 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

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.

See More

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

Keep scrolling for more

Learn More about sinus

Statistics for sinus

Last Updated

5 Mar 2019

Look-up Popularity

Time Traveler for sinus

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

See more words from the same century

Keep scrolling for more

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 How to pronounce sinus (audio) \

Kids Definition of sinus

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

sinus

noun
si·​nus | \ ˈsī-nəs How to pronounce sinus (audio) \

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

Keep scrolling for more

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

Comments on sinus

What made you want to look up sinus? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

a shady place in a garden or forest

Get Word of the Day daily email!

Test Your Vocabulary

Original Meanings Quiz

  • rembrandt-painting-a-young-scholar-and-his-tutor
  • Which of the following is the earliest known sense of the word awe?
How Strong Is Your Vocabulary?

Test your vocabulary with our 10-question quiz!

TAKE THE QUIZ
SCRABBLE® Sprint

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!