noun, plural si·nus·es. a curve; bend.
a curving part or recess.
Anatomy any of various cavities, recesses, or passages, as a hollow in a bone, or a reservoir or channel for venous blood. one of the hollow cavities in the skull connecting with the nasal cavities. an expanded area in a canal or tube. Pathology a narrow passage leading to an abscess or the like.
Botany a small, rounded depression between two projecting lobes, as of a leaf.
Origin of sinus 1590–1600; < Latin sinus (stem sinu- ) bent or curved surface, curve, fold
Related forms si·nus·like , adjective Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
Examples from the Web for sinus Contemporary Examples of sinus A fair number explicitly ask for an antibiotic, to cover the possibility that it is “bronchitis” or a “sinus infection.”
Benign secondary headaches include headaches associated with the cold, flu, or sinus infections.
First of all, migraines often are misdiagnosed as sinus headaches.
One of the entries reads: “I spoke with a doctor for a long time about my sinus infections.”
Historical Examples of sinus He has no bag like the Hebrew slinger, no sinus like the Roman.
He inserted the glowing jewel in the folds of the sinus of her dress.
When there is a notch or sinus at the anterior extremity, it is said to be emarginated.
The symbol sv for sinus versus occurs in the Clavis of 1631.
A process of the face, which enters the notch or sinus of the eye.
British Dictionary definitions for sinus noun plural -nuses anatomy any bodily cavity or hollow space a large channel for venous blood, esp between the brain and the skull any of the air cavities in the cranial bones pathol a passage leading to a cavity containing pus
botany a small rounded notch between two lobes of a leaf, petal, etc
an irregularly shaped cavity
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Word Origin for sinus C16: from Latin: a curve, bay
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for sinus n. "hollow curve or cavity in the body," early 15c., from Medieval Latin sinus , from Latin sinus "bend, fold, curve, a bent surface; a bay, bight, gulf; a fold in land;" also "fold of the toga about the breast," hence "bosom," and figuratively "love, affection, intimacy; interior, inmost part;" of unknown origin.
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Online Etymology Dictionary, © 2010 Douglas Harper
n. A depression or cavity formed by a bending or curving.
A channel for the passage of blood or lymph, without the coats of an ordinary vessel, such as the blood passages in the gravid uterus or in the cerebral meninges.
Any of various air-filled cavities in the bones of the skull, especially one communicating with the nostrils.
A dilatation in a blood vessel.
A fistula or tract leading to a pus-filled cavity.
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The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
A cavity or hollow space in a bone of the skull, especially one that connects with the nose.
A channel for the passage of a body fluid, such as blood.
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The American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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