Definition of scoria in English:



  • 1A cindery, vesicular basaltic lava, typically having a frothy texture.

    • ‘Small vesicular pieces of volcanic material, scoria, collect around the vent to form a cinder cone.’
    • ‘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.’
    • ‘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.’
    1. 1.1 Slag separated from molten metal during smelting.


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.