/ Dictionary / Index P plastic flow: Meaning and Definition of Find definitions for: plas'tic flow' Pronunciation: [key] deformation of a material that remains rigid under stresses of less than a certain intensity but that behaves under severer stresses approximately as a Newtonian fluid. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. plastic explosive plastic foam Related Content Daily Word Quiz: careening Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language