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

Rounding out the multitool's features are three slots for optional glow-in-the-dark vials of tritium, to help find the thing at night or in a coal mine. —Ben Coxworth, New Atlas, 13 Dec. 2024

This example has a tritium dial, which has aged to a pleasant off-white color against the navy dial. —Allen Farmelo, Robb Report, 13 Dec. 2024

Muons displace electrons in the hydrogen atoms, resulting in hydrogen molecules made up of a deuterium and a tritium atom chemically bonded by a muon rather than an electron. —IEEE Spectrum, 3 Dec. 2024

The plants’ operator paid $1.2 million in 2010 to settle state and county complaints about numerous unreported leaks of radioactive tritium from both plants, located about 60 miles south of Chicago, dating back to the 1990s. —Karina Atkins, Chicago Tribune, 16 Nov. 2024

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