Deuterium (noun)

A stable isotope of hydrogen with one proton and one neutron in the nucleus, used in fusion reactors and as a tracer in biochemical studies.

Origin:

1930s: from german deuterium, from greek deuteros "second" + -ium (denoting a metallic element).

Examples:

1. Deuterium is an essential component in fusion reactions.
2. The scientists used deuterium to track the movements of molecules in the cell.
3. Deuterium is abundant in seawater and is relatively easy to obtain.
4. The use of deuterium in fusion reactors is still in its experimental stage.
5. The research team used deuterium to study the process of photosynthesis in plants.