What does radium mean?
Radium is a highly radioactive metallic chemical element, symbol Ra and atomic number 88, belonging to the alkaline-earth group. It was discovered in the late nineteenth century by Marie and Pierre Curie and named for the rays it emits. Radium compounds were once widely used in luminous paints, particularly on watch and clock dials, because they glowed faintly in darkness. This historical use created serious radiation hazards for workers who handled or painted the dials, and radium-related poisoning became a well-known public-health concern. Today, radium has largely been replaced by safer substances in commercial products, although certain radium isotopes remain relevant in specialized scientific and medical contexts. The word is therefore both a precise element name and a powerful historical reminder of the dangers associated with radiation.
nounA highly radioactive metallic element of the alkaline-earth group, with the symbol Ra and atomic number 88. Radium was formerly used in luminous paints and is now encountered mainly in historical and scientific contexts.
- A radioactive chemical element of the alkaline-earth group, with the symbol Ra and atomic number 88.
- Radium-containing material or a radium isotope used historically in luminous paints and instruments.
"The archaeologist carefully handled the radium-instrumented dial as a museum conservator."
"Radium was once widely used on watch dials so that they could be read in the dark."
"The laboratory tested the samples for radium and other radioactive contaminants."
Usually treated as an uncountable noun; plural usage is uncommon and generally occurs when referring to separate radium sources or samples.
"The laboratory compared two radiums recovered from different historical instruments."
Radium once made watch dials glow in the dark, but its beautiful light came from a dangerously radioactive element.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does radium come from?
The word radium was coined in the late nineteenth century from the Latin radius, meaning “ray,” in reference to the radioactive rays emitted by the newly discovered element. It belongs to a family of English words derived from Latin roots associated with rays and radiation, including radius, radiant, radiation, and radian. The scientific naming reflects the element's most striking early property: its energetic emanation of radiation.
How radium is actually used
In modern technical and historical writing, radium usually refers to the chemical element as an uncountable noun. In general usage, it often evokes radioluminescence, early medical treatments, occupational illness, and Marie Curie's pioneering research.
Easily confused with radium
Radium is a metallic chemical element, whereas radon is a radioactive noble gas that can be released from radium-containing materials.