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# radium

noun (radium — uncountable)

«radium» in the English dictionary: everyday — its meanings, how the lessons use it, and examples, each with its tree on Mova.

## Everyday

A rare, radioactive metal element (symbol Ra) that gives off dangerous radiation and glows faintly in the dark. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/R/radium/#m1)

### In the lessons

In science lessons radium is linked with Marie and Pierre Curie, who discovered it, and with learning about radioactivity. In history lessons it is a warning story: people once put radium in watch paint, toothpaste and drinks, not knowing it was harmful; the "Radium Girls" who painted glowing watch faces became very ill. It tells the reader about danger hidden in something that looks magical.

### Examples

- Marie Curie discovered radium with her husband Pierre. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/R/radium/#x1)
- Radium glows with a faint blue-green light. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/R/radium/#x2)
- Radium is radioactive, so it is very dangerous to touch. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/R/radium/#x3)
- Old watches had radium paint so you could read them in the dark. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/R/radium/#x4)
- The Radium Girls got ill from licking their paintbrushes. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/R/radium/#x5)
- Radium's symbol in the periodic table is Ra. [tree →](https://mova.elamur.ai/free/en/corpora/dictionaries/school/R/radium/#x6)

### Note

Uncountable: "radium is", not "a radium". Chemical symbol Ra, atomic number 88. Myth from long ago: radium was sold as healthy; it is not. Do not confuse with "radius" (a line from the centre of a circle).

## On Mova

- [Trees and pragmatics of «radium» in the school dictionary](https://mova.elamur.ai/free/en/corpora/dictionaries/school/R/radium/): every meaning and example parsed by Mova, with its dependency tree and frames.
- [«radium» in the school dictionary](https://mova.elamur.ai/free/en/dictionaries/school/w/radium.html) on Mova free.