Oblate also refers to a member of the Roman Catholic religious order of the Missionary Oblates of Mary Immaculate, or in some cases to a lay or religious person who has officially associated himself (or herself) with a monastic community such as the Benedictines for reasons of personal enrichment without actually assuming a monastic lifestyle.

An oblate spheroid is an ellipsoid having a shorter axis and two equal longer axes (see the spheroid page for a picture).

Oblateness is a measure for a planet that is a spheroid in shape, bulging outward in the center due to its rotation. Effectively the (fictitious) centrifugal force fights against gravity causing the planet to look more like a sphere stretched at the equator.

Mathematically, oblateness may be defined as

where R_e the equatorial radius and R_p is the polar radius. The approximation is valid in the case of a fluid planet of uniform density; it is a function of the Newtonian constant of gravitation G, the rotation period T and the density ρ.