Definition of scoria in English:


nounPlural scoriae

mass noun
  • 1Basaltic lava ejected as fragments from a volcano, typically with a frothy texture.

    ‘chunks of black scoria’
    count noun ‘the village lay half silted up under black scoriae and dust’
    • ‘Small vesicular pieces of volcanic material, scoria, collect around the vent to form a cinder cone.’
    • ‘It's always slightly warmer on Rangitoto thanks to the black scoria, but the 360 degree view of the gulf and the volcano-studded cityscape of Auckland is matchless.’
    • ‘Some of these cones are now barely recognisable, having been excavated for the volcanic cinder, scoria, used to build the roads of Auckland.’
    • ‘Alluvial, colluvial or chemically formed gravel, clayey gravel, sandstone, limestone, tuff, scoria are examples of marginal materials.’
    • ‘They cut steps in the frozen snow and made good progress along a ridge of ‘rugged scoriae’ which took them to the summit.’
  • 2Slag separated from molten metal during smelting.

    ‘the scoria has been expelled completely from the mercury’


Late Middle English (denoting slag from molten metal): via Latin from Greek skōria ‘refuse’, from skōr ‘dung’. The geological term dates from the late 18th century.