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sinus

[ sahy-nuhs ]
/ ˈsaɪ nəs /
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noun, plural si·nus·es.
a curve; bend.
a curving part or recess.
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.
Pathology. a narrow passage leading to an abscess or the like.
Botany. a small, rounded depression between two projecting lobes, as of a leaf.
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Origin of sinus

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

OTHER WORDS FROM sinus

si·nus·like, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use sinus in a sentence

British Dictionary definitions for sinus

sinus
/ (ˈsaɪnəs) /

noun plural -nuses
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
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

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

Scientific definitions for sinus

sinus
[ sīnəs ]

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.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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