tritium

noun

tri·​ti·​um ˈtri-tē-əm 

ˈtri-shē-

: a radioactive isotope of hydrogen that has one proton and two neutrons in its nucleus and that has three times the mass of ordinary hydrogen

—symbol T

Examples of tritium in a Sentence

Recent Examples on the Web

Meanwhile, laser inertial confinement works by concentrating a battery of high-energy lasers on a single spot where there's a cryogenic pellet of deuterium and tritium, creating a shockwave as the pellet implodes and fuses the atoms. —David Szondy, New Atlas, 8 July 2024

This would necessitate an extended shutdown after initial experiments before the reactor could be used at progressively higher energies, using more potent deuterium and deuterium/tritium plasmas. —John Timmer, Ars Technica, 5 July 2024

Radium continued to be used on military watches through the mid-20th century, and was finally phased out in favor of less dangerous tritium. —Oren Hartov, Robb Report, 13 June 2024

These require heavy forms of hydrogen—deuterium and tritium—for the fusion stage of the device, which is triggered by a plutonium or uranium fission bomb. —Siegfried S. Hecker, Foreign Affairs, 4 Dec. 2017

Word History

Etymology

New Latin, from Greek tritos third — more at third entry 1

First Known Use

1933, in the meaning defined above

Kids Definition

tritium

noun

tri·​ti·​um ˈtrit-ē-əm  ˈtrish-ē- 

: a rare radioactive form of hydrogen having atoms with three times the mass of ordinary light hydrogen atoms

Medical Definition

tritium

noun

tri·​ti·​um ˈtrit-ē-əm  ˈtrish-ē- 

: a radioactive isotope of hydrogen that has three times the mass of ordinary hydrogen

—symbol T