frus·​tum ˈfrə-stəm How to pronounce frustum (audio)
plural frustums or frusta ˈfrə-stə How to pronounce frustum (audio)
: the basal part of a solid cone or pyramid formed by cutting off the top by a plane parallel to the base
also : the part of a solid intersected between two usually parallel planes

Examples of frustum in a Sentence

Recent Examples on the Web The case of the 24-Seconde Architecture is shaped like a convex conical frustum. Carol Besler, Robb Report, 5 July 2022 The EmDrive test device used by White and his colleagues was a copper frustum—a cone with its top lopped off—that was just under a foot long. Daniel Oberhaus, Wired, 8 May 2020

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'frustum.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


New Latin, from Latin, piece, bit — more at bruise entry 2

First Known Use

1658, in the meaning defined above

Time Traveler
The first known use of frustum was in 1658

Dictionary Entries Near frustum

Cite this Entry

“Frustum.” Dictionary, Merriam-Webster, Accessed 24 Apr. 2024.

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