The shape of the Earth is best described as a Geoid, which is a 3D model of the Earth's shape that takes into account the planet's gravitational field and rotation. In other words, the Earth is not a perfect sphere, but rather an irregularly shaped object that bulges at the equator and is flattened at the poles due to the centrifugal force caused by its rotation. The geoid takes into account these variations in shape and gravity to create a model that accurately represents the Earth's surface and gravitational field. An eclipse is a celestial event in which the Earth, Moon, and Sun align in a particular way, while a cuboid is a geometrical shape with six rectangular faces. Therefore, neither of these terms accurately describes the shape of the Earth. "Round" is a vague term that could be used to describe the Earth, but it doesn't provide as much detail as the term "Geoid" does.