Word.ws English Dictionary

neutronium

/njuːˈtɹəʊni.əm/US/nuˈtɹoʊni.əm/

neutronium noun: a material composed entirely of neutrons.

Noun

neutronium (uncountable)

  1. A material composed entirely of neutrons.
    Synonyms:
    n, nn (polyneutron), N (nilium), Nt (neutronium, neutrium), nn
  2. A hypothetical gravitationally bound system of a neutron and an antineutron (the onium of a neutron), not predicted to exist under normal circumstances.

Synonyms of neutronium

5 more synonymsFewer synonyms

Antonyms

  • antielement 0
  • antielement zero
  • antineutrium
  • antineutronium
  • antinilium

Origin of neutronium

From neutron + -ium. Coined by scientist Andreas von Antropoff in 1926 (before the discovery of the neutron in 1931; neutrons had been predicted to exist in 1920).

Words formed from neutronium

Questions about neutronium

What does neutronium mean?
Neutronium means a material composed entirely of neutrons.
What part of speech is neutronium?
Neutronium is a noun.
How do you pronounce neutronium?
Neutronium is pronounced /njuːˈtɹəʊni.əm/ (UK).

Words near neutronium in the dictionary

  1. neutron-rich
  2. neutron-richer
  3. neutron-richest
  4. neutronic
  5. neutronics
  6. neutronium
  7. neutronization
  8. neutrons
  9. neutropaenia
  10. neutropaenias
  11. neutropaenic

Source and license

Adapted from Wiktionary: neutronium (page history and authors). Text available under the Creative Commons Attribution-ShareAlike 4.0 license. Word.ws reformatted the entry and added links. Wiktionary data of 2026-09-02.

Last updated:

Pronunciation audio from Wikimedia Commons, each file under its own free license: LL-Q1860 (eng)-Vealhurl-neutronium.wav.

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