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

There are no requirements to measure radium concentrations or demonstrate that the brine works for its new intended use. — Nathaniel Warner, The Conversation, 24 July 2026

Caltech researchers have created cold molecules containing the radioactive element radium for the first time, opening a new way to investigate why the universe is made mostly of matter instead of equal parts matter and antimatter. — Neetika Walter, Interesting Engineering, 17 July 2026

Generally, a quick Google search will lead you to your state’s specific guidelines for radium disposal. — Wendy Rose Gould, Martha Stewart, 17 July 2026

The Louviers Water & Sanitation District's ion exchange filtration system that removes radium. — Olivia Young, CBS News, 29 Apr. 2026

Word History

Etymology

New Latin, from Latin radius ray

First Known Use

1898, in the meaning defined above

Phrases Containing radium

• radium therapy

Rhymes for radium

• palladium
• vanadium
• stadium

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