SPHEROID, n. [sphere and form.] A body or figure approaching to a sphere, but not perfectly spherical. A spheroid is oblate or prolate. The earth is found to be a oblate spheroid that is, flatted at the poles, whereas some astronomers formerly supposed it to be prolate or oblong.
Source: Webster's 1828 American Dictionary ↗ · public-domain · returned verbatim, no AI