Definition of -ium in English:

-ium

suffix

  • 1Forming nouns adopted unchanged from Latin (such as alluvium) or based on Latin or Greek words (such as euphonium)

  • 2Forming names of metallic elements.

    ‘cadmium’
    ‘magnesium’
  • 3Denoting a region of the body.

    ‘pericardium’
  • 4Denoting a biological structure.

    ‘mycelium’

Origin

Modern Latin in -ium, -ium, and -ium via Latin from Greek -ion.