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[sahy-nuh-soid] /ˈsaɪ nəˌsɔɪd/
noun, Mathematics
a curve described by the equation y = a sin x, the ordinate being proportional to the sine of the abscissa.
1815-25; sinus + -oid Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for sinusoid
  • In this experiment, a sinusoid is fed into the oscilloscope.
British Dictionary definitions for sinusoid


any of the irregular terminal blood vessels that replace capillaries in certain organs, such as the liver, heart, spleen, and pancreas
another name for sine curve
resembling a sinus
Word Origin
C19: from French sinusoïde. See sinus, -oid
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
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Word Origin and History for sinusoid

1823 in mathematics; 1900 in physiology, from sinus + -oid. Related: Sinusoidal.

Online Etymology Dictionary, © 2010 Douglas Harper
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sinusoid in Medicine

sinusoid si·nu·soid (sī'nə-soid', -nyə-)
Any of the venous cavities through which blood passes in various glands and organs, such as the adrenal gland and the liver. adj.
Resembling a sinus.

si'nu·soi'dal (-soid'l) adj.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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Encyclopedia Article for sinusoid

irregular tubular space for the passage of blood, taking the place of capillaries and venules in the liver, spleen, and bone marrow. The sinusoids form from branches of the portal vein in the liver and from arterioles (minute arteries) in other organs. The walls of the sinusoids are lined with phagocytic cells, called Kupffer cells, that digest old red blood cells and clear the bloodstream of toxins.

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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