Ellipsoid
- A three-dimensional geometric surface, all of whose plane sections are either ellipses or circles. It is a closed surface that is a higher-dimensional analogue of an ellipse. nounThe planet Earth is often approximated as an oblate ellipsoid due to its equatorial bulge.In mathematics, an ellipsoid can be described by the equation of a quadric surface.
- In anatomy, a structure or organ that is shaped like an ellipsoid. nounThe ellipsoid shape of the lens in the human eye helps focus light onto the retina.Certain types of cells in the body can take on an ellipsoid form under specific conditions.