/ Dictionary / Index C cesium 137: Meaning and Definition of Find definitions for: cesium 137 Pronunciation: [key] — Chem. Chem. the radioactive cesium isotope with mass number 137 and a half-life of 33 years: used for gamma irradiation of certain foods and for radiation therapy. Also called Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. cesium České Budějovice Related Content Daily Word Quiz: alacrity Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language