楕だ円えん面めん

noun

ellipsoid

A mathematical term for a three-dimensional surface whose plane sections are ellipses or circles. Used in geometry and related fields.

• 地ち球きゅうは完かん全ぜんな球きゅうではなく、楕だ円えん面めんに近ちかい形かたちをしている。

  The Earth is not a perfect sphere; it has a shape close to an ellipsoid.