Radium

Part of speech: noun

Pronunciation: /ˈɹeɪ.dɪ.əm/

Definitions

1. A rare, radioactive metallic element that is utilized in some medical treatments and has historical significance in luminescent materials and instruments
2. This element emits significant radiation, finding application in cancer therapy while being part of early 20th-century glow-in-the-dark products
3. A highly radioactive element that occurs naturally and is known for its use in certain cancer treatments and its role in early luminescent products

Etymology: Radium was named in 1898 by Pierre and Marie Curie, who had isolated it from pitchblende and found that it glowed on its own. The name was built to fit the discovery: the Curies took the Latin "radius", meaning ray, and gave the new element an ending that chemists used for metals. Its French coinage came from "radioactif", the word the Curies helped establish for substances that emit rays spontaneously. The name's ancestry is therefore a mix of Latin and French. The Latin "radius" is a word for a spoke or a beam of light, and the French "radio-" prefix takes that root into the language of radiation. The "-ium" ending, which chemists have used since the nineteenth century for metallic elements such as "sodium", tied radium to the family of known metals.