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

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

A piece of a cone like this is called a frustum of a cone.

From Textbooks • Mar. 30, 2016

Figure 6.42 A frustum of a cone can approximate a small part of surface area.

From Textbooks • Mar. 30, 2016

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

From Textbooks • Mar. 30, 2016

This gave the base of the hollow cylinder, which would be equal to the frustum of a cone of like altitude; and another multiplication by the length produced the entire cubic content.

From The Boy Tar by Read, Edward