ˈtrid.ēəm, -itē- also -ishē- noun
( -s )
Etymology: New Latin, from trit- + -ium
: the radioactive isotope of hydrogen that has atoms of three times the mass of ordinary light hydrogen atoms, that has a half-life of about 12.5 years and emits beta rays to form helium of mass number 3, and that can be produced by bombardment of lithium with neutrons — symbol H 3 , 3 H, T