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[puh-rab-uh-loid] /pəˈræb əˌlɔɪd/
noun, Geometry
a surface that can be put into a position such that its sections parallel to at least one coordinate plane are parabolas.
1650-60; parabol(a) + -oid
Related forms
[puh-rab-uh-loid-l, par-uh-buh-] /pəˌræb əˈlɔɪd l, ˌpær ə bə-/ (Show IPA),
adjective Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for paraboloid
  • The ideal concentrator shape is a paraboloid of revolution.
  • Both these factors the form of a frustum of a paraboloid, then the equations can affect displacement.
  • The density profile for a typical experimental condensate is thus an inverted paraboloid when the confining potential is harmonic.
  • The paraboloid shape is perfect for focusing the sunlight on the tube.
  • It is preferable to use a cardioid condenser rather than a paraboloid condenser for darkfield fluorescent microscopy.
  • The antennas are high-gain, circular cross-section paraboloid reflectors or conical horn reflectors and are highly collimating.
British Dictionary definitions for paraboloid


a geometric surface whose sections parallel to two coordinate planes are parabolic and whose sections parallel to the third plane are either elliptical or hyperbolic. Equations x²/a² ± y²/b² = 2cz
Derived Forms
paraboloidal, adjective
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
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paraboloid in Science
A surface having parabolic sections parallel to a single coordinate axis and elliptic sections perpendicular to that axis.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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Encyclopedia Article for paraboloid

an open surface generated by rotating a parabola (q.v.) about its axis. If the axis of the surface is the z axis and the vertex is at the origin, the intersections of the surface with planes parallel to the xz and yz planes are parabolas (see , top). The intersections of the surface with planes parallel to and above the xy plane are circles. The general equation for this type of paraboloid is x2/a2 + y2/b2 = z

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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