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
Dunning pitched well in his return from a serious sinus infection suffered in Minnesota allowing only three hits in five innings of work with six strikeouts and four walks in the Rangers’ 6-1 victory over the Arizona Diamondbacks on Wednesday.
—
Lawrence Dow, Fort Worth Star-Telegram, 30 May 2024
Additionally, the Lung Institute highlights that salt particles in the air can have a therapeutic effect on the respiratory system, reducing uncomfortable symptoms like congestion and sinus pressure.
—Allison Palmer, Charlotte Observer, 28 May 2024
The plan was to put a plate in my eye socket to keep my eye from sinking into my sinus cavity.
—Chelsea Myslik, Peoplemag, 24 May 2024
The one thing that can help your itchy eyes, sneezing, and sinus headaches?
—Leonora Epstein, Peoplemag, 22 May 2024
See all Example Sentences for sinus 
Lawrence Dow, Fort Worth Star-Telegram, 30 May 2024
Additionally, the Lung Institute highlights that salt particles in the air can have a therapeutic effect on the respiratory system, reducing uncomfortable symptoms like congestion and sinus pressure.
—Allison Palmer, Charlotte Observer, 28 May 2024
The plan was to put a plate in my eye socket to keep my eye from sinking into my sinus cavity.
—Chelsea Myslik, Peoplemag, 24 May 2024
The one thing that can help your itchy eyes, sneezing, and sinus headaches?
—Leonora Epstein, Peoplemag, 22 May 2024
See all Example Sentences for sinus
These examples are programmatically compiled from various online sources to illustrate current usage of the word 'sinus.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.
Dictionary Entries Near sinus
Cite this Entry
“Sinus.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/sinus. Accessed 8 Jun. 2024.
Copy CitationKids Definition
Medical Definition
sinus
noun
si·nus
ˈsī-nəs 
: 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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