FRUSTUM

frustum

(noun) a truncated cone or pyramid; the part that is left when a cone or pyramid is cut by a plane parallel to the base and the apical part is removed

Source: WordNet® 3.1

Etymology

Noun

frustum (plural frustums or frusta)

A cone or pyramid whose tip has been truncated by a plane parallel to its base.

A portion of a sphere, or in general any solid, delimited by two parallel planes.

Usage notes

The misspelling frustrum is by incorrect analogy with frustrate, also of Latin origin.

• (portion of a sphere): The portion of the surface of a sphere delimited by parallel planes (i.e, the curved surface of a frustum) may be called a zone; however, that term is also sometimes used as a synonym of frustum.

Source: Wiktionary

Frus"tum, n.; pl. L. Frusta, E. Frustums. Etym: [L. fruslum piece, bit.]

1. (Geom.)

Definition: The part of a solid next the base, formed by cutting off the, top; or the part of any solid, as of a cone, pyramid, etc., between two planes, which may be either parallel or inclined to each other.

2. (Arch.)

Definition: One of the drums of the shaft of a column.

Source: Webster’s Unabridged Dictionary 1913 Edition