Definition of calx in English:


nounPlural calces

  • A powdery metallic oxide formed when an ore or mineral has been heated.

    • ‘The calx combines with a flux containing phlogiston-rich materials.’
    • ‘Other common names by which the compound is known include burnt lime, unslaked lime, fluxing lime, and calx.’
    • ‘Boyle knew the tin gained weight as the calx was formed.’
    • ‘The reason a metal formed when its calx was heated with charcoal was therefore because the phlogiston left the charcoal and united with the calx.’
    • ‘Then a French pharmacist named Pierre Bayen pointed out to Lavoisier that calx of mercury, which we would now call mercuric oxide, can be converted to mercury simply by heating.’


Late Middle English: from Latin, ‘lime’, probably from Greek khalix ‘pebble, limestone’.