/ Dictionary / Index P prismoid: Meaning and Definition of Find definitions for: pris•moid Pronunciation: (priz'moid), [key] — n. Geom. a solid having sides that are trapezoids and bases or ends that are parallel and similar but not congruent polygons. Cf.(def. 2). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: prismoid (Thesaurus) prism diopter prism spectrometer Related Content Daily Word Quiz: feline Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language