English Reference

Word

radium

Phoneticsra·di·um

US/ˈɹeɪdiəm/

UK/ɹˈeɪdiəm/

Definitions

01chemical element

B2 · Science

n. a rare, silvery metal that is radioactive and glows slightly in the dark.

n. a radioactive metallic element of the alkaline earth series, found in minute quantities in uranium ores.

“Marie Curie discovered radium and studied how its radiation could be used.”

“The discovery of radium revolutionized our understanding of atomic physics, though its intense radioactivity posed severe health risks to early researchers.”

Technical

Usage

Uncountable when referring to the element itself; countable when referring to a specific sample or isotope.

Synonyms

Ra

02shiny fabric

C2

n. a type of smooth, shiny cloth made from silk or similar materials.

n. a lustrous fabric woven from silk or synthetic yarns, characterized by its glossy finish.

“The vintage dress was made of a shimmering radium silk.”

“The boutique specialized in evening gowns crafted from radium, a fabric prized in the early twentieth century for its exceptional sheen.”

Archaic

Teaching tip

This sense is obsolete in modern fashion; learners will likely only encounter it in historical contexts or period literature.

Synonyms

03to treat with radiation

C2 · Medicine

v. to use radium to treat a disease like cancer.

v. to apply radium or its emissions for therapeutic purposes, particularly in the treatment of malignant tumours.

“Doctors used to radium the affected area to stop the growth.”

“Before the development of modern linear accelerators, physicians would radium the site of a tumour using specialized needles or plaques.”

Archaic · Technical

Usage

Transitive verb; usually takes the medical condition or the body part as a direct object.

Synonyms

irradiate

Real-World Examples

“A team of researchers from Penn State is trying to better understand the environmental impacts of these sites—specifically, whether fracking is increasing radium content in local drinking water.”
Phys.org · 24 Aug 2026

Etymology

Borrowed from French radium, from rad(ioactif) (“radioactive”) + -ium (suffix used to form the names of metallic elements).

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Word family

radiumNounradonNoun

Related words

This entry

Level
C2 · Proficiency
Frequency
Occasional
Updated

Scan code

englishreference.com/q/radium

English Reference