frustum
/ˈfrʌstəm/
noun
- The part of a solid (such as a cone or pyramid) that remains after the top is cut off by a plane parallel to the base.
- A lampshade is often shaped like the frustum of a cone.
- The bucket is a frustum, wider at the top than at the bottom.
- In geometry class, we calculated the volume of a frustum of a pyramid.