The powdery black stuff that's sometimes created when fuel burns is called soot. A chimney sweep's job is to clean all the soot and ash from inside a chimney.

Soot is mostly made of carbon, and it forms when matter burns incompletely. Engines, burning coal, and house fires are all sources of soot, and soot is a major contributor to air pollution around the world. It's dangerous for people to breathe too much soot into their lungs. Soot comes from a Germanic root that literally means "what settles."

Definitions of soot

n a black colloidal substance consisting wholly or principally of amorphous carbon and used to make pigments and ink

carbon black, crock, lampblack, smut
Type of:
C, atomic number 6, carbon
an abundant nonmetallic tetravalent element occurring in three allotropic forms: amorphous carbon and graphite and diamond; occurs in all organic compounds

v coat with soot

Type of:
coat, surface
put a coat on; cover the surface of; furnish with a surface

Sign up, it's free!

Whether you're a student, an educator, or a lifelong learner, can put you on the path to systematic vocabulary improvement.