An "oblate spheroid" is a shape that is round like a sphere, but slightly flattened at the top and bottom. It looks like a stretched-out ball. Full definition
The equilibrium shape of a rotating star — or planet, for that matter — is not a sphere, but rather an flattened oblate spheroid. (scientificamerican.com)
Instead they work on the equatorial bulge; due to its own rotation, the Earth is not a perfect sphere but an oblate spheroid, with an equatorial diameter about 43 kilometers larger than its polar diameter. (sciencedaily.com)
A three - dimensional x-ray diffraction study of aspartate transcarbamylase to 5.5 - angstrom resolution, with the aid of four isomorphous heavy atom derivatives, indicates the presence of a central aqueous cavity approximating an oblate spheroid about 25 by 50 by 50 angstroms in dimension, within a molecule about 90 by 110 by 110 angstroms in largest dimensions. (science.sciencemag.org)