Wikipedia is surprisingly accurate on this, so I'll take it:
An Earth ellipsoid or Earth spheroid is a mathematical figure approximating the Earth's form, used as a reference frame for computations in geodesy, astronomy, and the geosciences. Various different ellipsoids have been used as approximations.
oblate spheroid, innit?
Gonna copy and paste this for both since you basically said the same thing:
https://en.wikipedia.org/wiki/Earth_ellipsoid#:~:text=An%20Earth%20ellipsoid%20or%20Earth,have%20been%20used%20as%20approximations.
Wikipedia is surprisingly accurate on this, so I'll take it:
So, yes. But also yes.