Radium (noun)

1. A radioactive element with the atomic number 88 and symbol Ra.
2. A radioactive metallic element that is present in minute amounts in uranium ores and is used in small amounts in some types of cancer treatment.
3. A radioactive metallic element with atomic number 88 and symbol Ra.

Origin:

From new latin radium, from latin radius ("ra.y")

Examples:

1. Radium was discovered by Marie Curie.
2. Radium was used in early watches as a source of light.
3. Radium was used in cancer treatment.
4. Radium was used in some types of cancer treatment.
5. Radium was present in minute amounts in uranium ores.