/ Dictionary / Index P periodic table: Meaning and Definition of Find definitions for: pe'ri•od'ic ta'ble Pronunciation: (pēr'ē-od'ik, pēr"-), [key] — Chem. Chem. a table illustrating the periodic system, in which the chemical elements, formerly arranged in the order of their atomic weights and now according to their atomic numbers, are shown in related groups. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. periodic system periodide Related Content Daily Word Quiz: pugilist Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language