Definition of frustum
: 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
Origin and Etymology of frustum
New Latin, from Latin, piece, bit — more at bruise
First Known Use: 1658
Seen and Heard
What made you want to look up frustum? Please tell us where you read or heard it (including the quote, if possible).