/ Dictionary / Index P platinous: Meaning and Definition of Find definitions for: plat•i•nous Pronunciation: (plat'n-us), [key] — adj. Chem. containing bivalent platinum. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. platinotype platinum Related Content Daily Word Quiz: immense Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language