fly ash: Meaning and Definition of

fly' ash"

Pronunciation: [key]
  1. fine particles of ash of a solid fuel carried out of the flue of a furnace with the waste gases produced during combustion.
  2. such ash recovered from the waste gases, used chiefly as a reinforcing agent in the manufacture of bricks, concrete, etc.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.