frustum

American  

[fruhs-tuhm] / ˈfrʌs təm /

noun

Geometry.

plural

frustums, frusta

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.

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frustum British  

/ ˈfrʌstəm /

noun

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

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Etymology

Origin of frustum

1650–60; < Latin: piece, bit; probably akin to Old Irish brúid (he) breaks, Old English brȳsan to crush

Example Sentences

Figure 6.44 Calculating the lateral surface area of a frustum of a cone.

From Textbooks • Mar. 30, 2016

Let r1 and r2 be the radii of the wide end and the narrow end of the frustum, respectively, and let l be the slant height of the frustum as shown in the following figure.

From Textbooks • Mar. 30, 2016

Figure 2.44 Calculating the lateral surface area of a frustum of a cone.

From Textbooks • Mar. 30, 2016

Note that the slant height of this frustum is just the length of the line segment used to generate it.

From Textbooks • Mar. 30, 2016

The solids divided in given ratios are the sphere, the pyramid, the cone and a frustum thereof.

From The Legacy of Greece Essays By: Gilbert Murray, W. R. Inge, J. Burnet, Sir T. L. Heath, D'arcy W. Thompson, Charles Singer, R. W. Livingston, A. Toynbee, A. E. Zimmern, Percy Gardner, Sir Reginald Blomfield by Livingstone, R.W.