radium

noun

ra·​di·​um ˈrā-dē-əm 

often attributive

: an intensely radioactive metallic chemical element that occurs in combination in minute quantities in minerals (such as pitchblende or carnotite), emits alpha particles and gamma rays to form radon, and is used chiefly in the treatment of cancer and in radiographic devices see Chemical Elements Table

Examples of radium in a Sentence

Recent Examples on the Web

Other examples of naturally occurring carcinogens include radium, a chemical element known to cause cancer, and erionite, a mineral found in volcanic ash. —Emilie Le Beau Lucchesi, Discover Magazine, 27 May 2024

Notes & Opinions on 4-Digit Rolexes Rolex switched from radium to tritium in 1963. —Allen Farmelo, Robb Report, 7 May 2024

Scientists and historians now agree that radium was responsible for the workers’ illnesses. —Emilie Le Beau Lucchesi, Discover Magazine, 20 May 2024

Four-digit dials produced before 1963 will use radium luminescent paint, which some fear due to radioactivity. —Allen Farmelo, Robb Report, 7 May 2024

Word History

Etymology

New Latin, from Latin radius ray

First Known Use

1899, in the meaning defined above

Phrases Containing radium

• radium therapy

Kids Definition

radium

noun

ra·​di·​um ˈrād-ē-əm 

: a strongly radioactive shining white metallic element that is chemically similar to barium, occurs in combination in very small quantities in minerals (as pitchblende), and is used in the treatment of cancer see element

Medical Definition

radium

noun

ra·​di·​um ˈrād-ē-əm 

often attributive

: an intensely radioactive shining white metallic element that resembles barium chemically, that occurs in combination in minute quantities in minerals (as pitchblende or carnotite) principally as the isotope of mass number 226 formed from uranium 238, having a half-life of 1620 years, and emitting alpha particles and gamma rays to form radon, and that is used chiefly in luminous materials and in the treatment of cancer

—symbol Ra see Chemical Elements Table