/ Dictionary / Index P pentavalent: Meaning and Definition of Find definitions for: pen•ta•va•lent Pronunciation: (pen"tu-vā'lunt, pen-tav'u-), [key] — adj. Chem. having a valence of 5: pentavalent arsenic. quinquevalent (def. 2). Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: pentavalent (Thesaurus) pentatonism pentazocine Related Content Daily Word Quiz: ostracize Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language