Definition of "ellipsoid" [el•lip•soid]

• A geometric surface, all of whose plane sections are either ellipses or circles. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• ""The biological implementation of this mechanism is currently unknown, but there is evidence from a previous study that a brain area called the ellipsoid body (sometimes called the" fly motor cortex ") might be involved.""
• "But some mathematicians and scientists fear that the new solution could turn out to be like a Russian discovery of a few years back, called the ellipsoid method, which was beautiful but not very useful in solving the workaday problems at which simplex excels."
• "[T] he variety of shapes found in the neurons of a wheel-shaped brain structure called the ellipsoid body "are just amazing," Peng says."