fly ash

noun

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.

fly ash

noun

1. fine solid particles of ash carried into the air during combustion, esp the combustion of pulverized fuel in power stations

Word History and Origins

Origin of fly ash¹

First recorded in 1930–35