Definition of neutronium in English:

neutronium

noun

Science Fiction Astronomy
  • Very dense matter consisting of free neutrons, thought to exist in the interior of neutron stars where electrons and protons combine with each other as a result of extreme pressure.

Origin

1930s. From neutron + -ium, after German Neutronium.

Pronunciation

neutronium

/njuːˈtrəʊnɪəm/