fly ash /ˈflaɪ æʃ/ noun1 •A residue generated in the combustion of powdered coal or other materials, comprising the fine particles that rise with the flue gases; when generated industrially it is usually captured and can be recycled for use in construction materials.Among new freight vehicles was a prototype 21-ton wagon with pressure discharge for the conveyance of fly ash from power stations, […] — 1964
