Whats another term for the shape of the earth (oblate sphere)?
Edit: – I just re-read your question. The word you are trying to get is “Geoid”. Wiki defines it as “The geoid is that equipotential surface which would coincide exactly with the mean ocean surface of the Earth, if the oceans were in equilibrium, at rest, and extended through the continents”. I should have realised this immediately as I work with surveyors, and they rely on the Geoid for their calculations – it’s sort of like an averaged out model of the Earth. Wiki (where there is a good diagram, see below) goes on to say: “The gravity field of the earth is neither perfect nor uniform. A flattened ellipsoid is typically used as the idealized earth, but even if the earth were perfectly spherical, the strength of gravity would not be the same everywhere, because density (and therefore mass) varies throughout the planet. This is due to magma distributions, mountain ranges, deep sea trenches, and so on. “If that perfect sphere were then covered in water, the water would not be the same he
