frustum

名词 frustum:

1. a truncated cone or pyramid; the part that is left when a cone or pyramid is cut by a plane parallel to the base and the apical part is removed

frus.tum

n.（名词）
【复数】 frus.tums 或 frus.ta [-t…] 【数学】
The part of a solid, such as a cone or pyramid, between two parallel planes cutting the solid, especially the section between the base and a plane parallel to the base.
平截头体：切割立体的两个平面之间的立体的一部分，如圆柱体或角锥，尤指与底边平行的底边或平面间的部分

来源：
Latin [piece broken off]
拉丁语 [断的部分]