soot
n. uncountable B2 Upper Intermediate US //ˈsʊt// UK //sˈʊt// soot
n. the black powder that comes from burning things like wood or coal. It often collects inside chimneys or on walls near a fire.
n. a black, powdery substance consisting largely of amorphous carbon, produced by the incomplete combustion of organic matter.
The chimney was full of black soot.
After the fireplace was cleaned, a thin layer of soot settled on the white rug in the living room.
Environmental scientists monitor the accumulation of soot in urban areas, as these fine carbon particles contribute significantly to both air pollution and the acceleration of glacial melting.