/ Dictionary / Index P periodate: Meaning and Definition of Find definitions for: per•i•o•date Pronunciation: (pu-rī'u-dāt"), [key] — n. Chem. a salt of a periodic acid, as sodium periodate, NaHIO. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. period periodic Related Content Daily Word Quiz: simian Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language