noun Etymology: New Latin, from Greek deuteros second Date: 1933 an isotope of hydrogen that has one proton and one neutron in its nucleus and that has twice the mass of ordinary hydrogen
DEUTERIUM
Meaning of DEUTERIUM in English
Merriam Webster. Explanatory English dictionary Merriam Webster. Толковый словарь английского языка Мерриам-Уэбстер. 2012