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# frustum

[fruhs-tuh m]
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noun, plural frus·tums, frus·ta [fruhs-tuh] /ˈfrʌs tə/. Geometry.
1. the part of a conical solid left after cutting off a top portion with a plane parallel to the base.
2. the part of a solid, as a cone or pyramid, between two usually parallel cutting planes.

## Origin of .css-1fxfie5{font-size:22px;}@media (max-width:768px){.css-1fxfie5{font-size:18px;margin:0 10px 10px 0;word-break:break-all;word-wrap:break-word;-webkit-hyphens:auto;-moz-hyphens:auto;-ms-hyphens:auto;hyphens:auto;line-height:22px;}}frustum

1650–60; < Latin: piece, bit; probably akin to Old Irish brúid (he) breaks, Old English brȳsan to crush
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

## Examples from the Web for frustum

### Historical Examples

• #### Wa'al, jest cut off the top, and what's left will be the frustum.

The Light Keepers

James Otis

• #### Then follows, in most textbooks, a theorem relating to the volume of a frustum.

The Teaching of Geometry

David Eugene Smith

• #### The top of the piston forms the frustum of the cone and the pistons are 110 mm.

Aviation Engines

Victor Wilfred Pag

• #### A stick of timber is in the shape of the frustum of a square pyramid, the lower base being 22 in.

The Psychology of Arithmetic

Edward L. Thorndike

• #### This leads to the corollary concerning the lateral area of the frustum of a regular pyramid.

The Teaching of Geometry

David Eugene Smith

British Dictionary definitions for frustum

# frustum

noun plural -tums or -ta (-tə)
1. geometry
1. the part of a solid, such as a cone or pyramid, contained between the base and a plane parallel to the base that intersects the solid
2. the part of such a solid contained between two parallel planes intersecting the solid
2. architect a single drum of a column or a single stone used to construct a pier

## Word Origin

C17: from Latin: piece; probably related to Old English brӯsan to crush, bruise
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

## Word Origin and History forfrustum

### n.

1650s, from Latin frustum "piece broken off," from PIE *bhrus-to-, from root *bhreu- "to cut, break up."