Breadcrumb Home > Dictionary > Index A actinism: Meaning and Definition of Find definitions for: ac•tin•ism Pronunciation: (ak'tu-niz"um), [key] — n. the property of radiation by which chemical effects are produced. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: actinism (Thesaurus) actinin actinium TrendingHere are the facts and trivia that people are buzzing about. Did Birds Evolve from Dinosaurs? The Twelve Dancing Princesses Current Events This Week: January 2023 African Americans by the Numbers Andersen's Fairy Tales: Contents The Celtic Twilight: A Teller of Tales ✖ Related Content Daily Word Quiz: saturnine Analogy of the Day: Today’s Analogy Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language