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sinus definition

si·nus (sī′nəs)

noun

  1. a bend or curve
  2. any cavity or hollow formed by a bending or curving
  3. Anat., Zool. any of various cavities, hollows, or passages; esp.,
    1. any of the air cavities in the skull opening into the nasal cavities
    2. a large channel for venous blood
    3. a dilated part in a blood vessel, etc.
  4. Bot. a rounded depression between two consecutive lobes, as of a leaf
  5. Med. a channel leading from a pus-filled cavity

Etymology: L, a bend, curve, fold

Webster's New World College Dictionary Copyright © 2009 by Wiley Publishing, Inc., Cleveland, Ohio.
Used by arrangement with John Wiley & Sons, Inc.

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