a solid having sides that are trapezoids and bases or ends that are parallel and similar but not congruent polygons.Compare prism(def 2).
Origin of prismoid
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
a prismatoid having an equal number of vertices in each of the two parallel planes and whose sides are trapeziums or parallelograms
Word Origin for prismoid
C18: from French prismoïde; see prism, -oid
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012