# 3d geometry question **URL:** \ **Category:** Factual Questions\ **Created:** [November 4, 2002, 1:25pm UTC](https://boards.straightdope.com/t/3d-geometry-question/135207 "2002-11-04T13:25:16Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![furt](https://avatars.discourse-cdn.com/v4/letter/f/439d5e/32.png) [@furt](https://boards.straightdope.com/u/furt)\ **Post date:** [November 4, 2002, 1:25pm UTC](https://boards.straightdope.com/t/3d-geometry-question/135207/1 "2002-11-04T13:25:16Z")
What is the name for a 3 dimensional trapezoid? I’m specifically looking for the name for a 4-sided pyramid with the tip cut off, or (if it makes nore sense this way), a cube in which every side is the same, but the bottom facet is ‘stretched’ larger. Sort of a cowbell shape. If more than one term applies, please give me all of them. It’s for a short story and I’ll pick whichever sounds best… ---
**Author:** ![ShadowWarrior](https://avatars.discourse-cdn.com/v4/letter/s/7993a0/32.png) [@ShadowWarrior](https://boards.straightdope.com/u/ShadowWarrior)\ **Post date:** [November 4, 2002, 2:11pm UTC](https://boards.straightdope.com/t/3d-geometry-question/135207/2 "2002-11-04T14:11:08Z")
would this be described as a trapezoidal prism? [http://www.themathlab.com/geometry/section10b/drawnets/trpprsnet.htm](http://www.themathlab.com/geometry/section10b/drawnets/trpprsnet.htm) this seems to be a site about cardboard boxes, but this one is the shape I’m imagining, and they call it a trapezoidal prism ---
**Author:** ![Jabba](https://avatars.discourse-cdn.com/v4/letter/j/b5e925/32.png) [@Jabba](https://boards.straightdope.com/u/Jabba)\ **Post date:** [November 4, 2002, 2:45pm UTC](https://boards.straightdope.com/t/3d-geometry-question/135207/3 "2002-11-04T14:45:09Z")
It’s a [frustrum](http://microgeometry.netfirms.com/content/equations.html). The same term is used for the corresponding part of a cone. ---
**Author:** ![typo\_mna](https://avatars.discourse-cdn.com/v4/letter/t/eb8c5e/32.png) [@typo\_mna](https://boards.straightdope.com/u/typo_mna)\ **Post date:** [November 4, 2002, 4:31pm UTC](https://boards.straightdope.com/t/3d-geometry-question/135207/4 "2002-11-04T16:31:12Z")
frustum, not frustrum