Definition of tritium in US English:

tritium

noun

Chemistry
  • A radioactive isotope of hydrogen with a mass approximately three times that of the common protium isotope.

    Discovered in 1934, tritium has two neutrons as well as a proton in the nucleus. It occurs in minute traces in nature and can be made artificially from lithium or deuterium in nuclear reactors; it is used as a fuel in thermonuclear bombs

    • ‘This particular arrangement of nucleons is unstable and so tritium readily undergoes radioactive decay to yield a helium atom.’
    • ‘These products contain tiny glass vials filled with a radioactive gas such as tritium.’
    • ‘Although tritium can be a gas, its most common form is in water, because, like non-radioactive hydrogen, radioactive tritium reacts with oxygen to form water.’
    • ‘Although many nuclei can be fused, this subject normally refers to fusion of hydrogen isotopes deuterium or tritium to form helium.’
    • ‘The isotopes tritium and helium - 3 were used to identify and date ground water recharged in the past 50 years.’

Origin

1930s: from modern Latin, from Greek tritos ‘third’.

Pronunciation

tritium

/ˈtridēəm//ˈtrɪdiəm/