radium A

American  

noun

Chemistry.

1. a substance, formed by decay of radon, that gives rise to radium B.

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Etymology

Origin of radium A

First recorded in 1900–05

Example Sentences

Katie Hafner: He told Meitner that where he'd expected to see radium, a heavy metal, he was instead finding barium, a much lighter element.

From Scientific American

She had radium - a radioactive substance - sewn into her cervix to try to kill off the tumour.

From BBC

Researchers have found high levels of radium, a radioactive element that increases the risk of different types of cancer, downstream of the facilities' outlets.

From Salon

It contained radium, a highly radioactive element, and the stuff was inescapable.

From Seattle Times

The active ingredient in these drinks was radium, a radioactive element that releases a packet of radiant energy with every atomic decay.

From Salon