frustum

[ fruhs-tuhm ]

noun

, Geometry.

, plural frus·tums, frus·ta [fruhs, -t, uh].

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.

frustum

/ 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

Word History and Origins

Origin of frustum¹

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

Word History and Origins

Origin of frustum¹

C17: from Latin: piece; probably related to Old English brӯsan to crush, bruise

Example Sentences

A scutoid is more complicated than a prismatoid, which is more complicated than a frusta, which is more complicated than a prism.

From Scientific American

Such constriction produces cells that are neither prisms nor frusta — but the shape that they form has had no name.

From Nature

Biologists had long assumed that these cells acquire the shape of frusta, as in a Roman arch.

From The New Yorker

“The whole building,” says Smeaton, “consisted of a simple figure, being an elegant frustum of a cone, unbroken by any projecting ornaments, or anything whereon the violence of the storm could lay hold.”

From Project Gutenberg

A stick of timber is in the shape of the frustum of a square pyramid, the lower base being 22 in. square and the upper 14 in. square.

From Project Gutenberg