Share this entry
tritium Syllabification: trit·i·um
Pronunciation: /ˈtridēəm/

Definition of tritium in English:


A radioactive isotope of hydrogen with a mass approximately three times that of the common protium isotope. (Symbol: T)

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

Example sentences
  • Although many nuclei can be fused, this subject normally refers to fusion of hydrogen isotopes deuterium or tritium to form helium.
  • 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.
  • These products contain tiny glass vials filled with a radioactive gas such as tritium.


1930s: from modern Latin, from Greek tritos 'third'.

Definition of tritium in:
Share this entry

What do you find interesting about this word or phrase?

Comments that don't adhere to our Community Guidelines may be moderated or removed.

Subscribe to remove ads and access premium resources