# radium

/ˈɹeɪdiəm/ (US) · /ɹˈeɪdiəm/ (UK)

Source: https://englishreference.com/word/radium
Updated: 2026-08-27

## Senses

### 1. chemical element

noun · CEFR B2 · Technical

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

For teachers: 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.

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

### 2. shiny fabric

noun · CEFR C2 · Archaic

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

For teachers: 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.

Teaching tip: This sense is obsolete in modern fashion; learners will likely only encounter it in historical contexts or period literature.

### 3. to treat with radiation

verb · CEFR C2 · Archaic · Technical

to use radium to treat a disease like cancer.

For teachers: 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.

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

## Examples

- The old clock hands were painted with radium to glow at night.
- Scientists in the early twentieth century discovered that radium could be used to treat certain types of cancer, though its dangers were not yet understood.
- The discovery of radium by the Curies revolutionized the field of radiochemistry, though the subsequent health risks associated with its handling eventually led to its replacement by safer isotopes.

---

From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.