neutronium
/njuːˈtrəʊnɪəm/Chiefly Science Fiction and Astronomy
noun
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.
- In Science Fiction frequently conceived of as a solid. Astrophysical research suggests that the condensed neutron material present in neutron stars is predominantly in a superfluid state..
Origin
1930s. From neutron + -ium, after German Neutronium.