Definition of nebulium in English:

nebulium

noun

Chemistry
historical
  • A hypothetical chemical element proposed in the 1860s to explain certain lines in the spectra of nebulae, later discovered to arise from forbidden transitions in oxygen and nitrogen ions.

    [as modifier] ‘nebulium lines’

Origin

Late 19th century: from nebula + -ium.

Pronunciation:

nebulium

/nɛˈbjuːlɪəm/