Definitions

1. noun

A rare and radioactive isotope of hydrogen, with the atomic number 3, used in self-powered lighting devices and other applications.

“The scientist studied the properties of tritium in the laboratory.”

2. noun

A unit of measurement for the activity of radioactive materials, equal to 3.7 x 10^10 disintegrations per second.

“The geiger counter measured the tritium levels in the contaminated area.”