/ Dictionary / Index B barium 140: Meaning and Definition of Find definitions for: barium 140 Pronunciation: [key] — Chem. Chem. the radioactive isotope of barium having a mass number of 140 and a half-life of 12.8 days, used chiefly as a tracer. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. barium barium bromate Related Content Daily Word Quiz: paradox Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language