deuterium

noun

deu·​te·​ri·​um dü-ˈtir-ē-əm 

also dyü-

: an isotope of hydrogen that has one proton and one neutron in its nucleus and that has twice the mass of ordinary hydrogen

—symbol D

called also heavy hydrogen

Examples of deuterium in a Sentence

Recent Examples on the Web

Deuterated water refers to water in which one hydrogen atom is replaced with deuterium, a heavy hydrogen isotope that has an atomic nucleus composed of one proton and one neutron. —Robert Lea, Space.com, 23 Apr. 2026

As their interior temperatures rise, proton-deuterium fusion begins. —Big Think, 20 Apr. 2026

Another experimental variation in 2016 involved replacing the electron with a muon in a deuterium atom—a heavier isotope of hydrogen, with a neutron as well as a proton and an electron. —ArsTechnica, 14 Apr. 2026

Its fuel, deuterium, can be derived from water. —Neetika Walter, Interesting Engineering, 4 Mar. 2026

Word History

Etymology

New Latin, from Greek deuteros second

First Known Use

1933, in the meaning defined above

Phrases Containing deuterium

• deuterium oxide

Rhymes for deuterium

• agrobacterium
• corynebacterium
• mycobacterium
• bacterium
• delirium
• imperium
• puerperium
• venereum
• cyanobacterium
• magisterium
• ministerium

Kids Definition

deuterium

noun

deu·​te·​ri·​um d(y)ü-ˈtir-ē-əm 

: the hydrogen isotope that is twice the mass of ordinary hydrogen

called also heavy hydrogen

Medical Definition

deuterium

noun

deu·​te·​ri·​um d(y)ü-ˈtir-ē-əm 

: an isotope of hydrogen that has one proton and one neutron in its nucleus and that has twice the mass of ordinary hydrogen

called also heavy hydrogen