Deuterium

//djuːˈtɪɹi.əm// noun

noun ·Uncommon ·Advanced level

Definitions

Noun
  1. 1
    An isotope of hydrogen with one proton and one neutron in each atom - ²₁H. uncountable

    "Heavy water is "heavy" because it contains deuterium."

  2. 2
    an isotope of hydrogen which has one neutron (as opposed to zero neutrons in hydrogen) wordnet
  3. 3
    An atom of this isotope. countable

    "There were about 80 deuteriums for every million protiums, and virtually no tritium."

Example

More examples

"Scientists from the Lawrence Livermore National Laboratory report they were able to create a type of fusion reaction by bombarding a microscopic pellet of fuel with beams from 192 powerful lasers to compress its component parts — hydrogen isotopes known as deuterium and tritium — and fuse them together at the atomic level."

Etymology

From deutero- + -ium. Coined by American physical chemist Harold Urey, from Ancient Greek δεύτερος (deúteros, “second”).

Related phrases

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.