Definition of hassium in US English:



  • The chemical element of atomic number 108, a very unstable element made by high-energy atomic collisions.

    See also hahnium
    • ‘The researchers established that hassium forms a gaseous oxide similar to that of osmium, confirming that hassium, like osmium, is a member of group 8 of the periodic table and should be placed directly under it.’
    • ‘Hassium does not occur in nature, and it has no isotopes that last long enough to allow significant quantities to be accumulated.’
    • ‘Element 108 is called hassium, after the German state of Hesse wherein Darmstadt is situated.’
    • ‘One potential candidate for such a long-living element is hassium, which contains about 180 neutrons.’
    • ‘They have anywhere from 13 isotopes to one isotope (e.g., hassium and meitnerium).’


Modern Latin, from Latin Hassias ‘Hesse’ (the German state); it was discovered in Darmstadt in 1984.