/ Dictionary / Index P Polybius: Meaning and Definition of Find definitions for: Po•lyb•i•us Pronunciation: (pu-lib'ē-us), [key] — n. c205–c123b.c.,Greek historian. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. polybasite polybrominated biphenyl Related Content Daily Word Quiz: lunar Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language