n. In glass-making: The reheating of partially formed glassware in a flashing-furnace to restore the plastic condition, and to smooth rough edges.n. The act or process of heating a globe of blown glass, and giving it a rapid rotary motion, so that the opening already made in it will widen till the globe flashes suddenly into a flat disk.n. A mode of coating a globe of hot colorless glass with a film of colored glass, usually red, and blowing them together until they flash into a disk.n. In architecture, pieces of lead, zinc, or other metal, used to protect the joining when a roof comes in contact with a wall, or when a chimney-shaft or other object comes through a roof, and the like.n. In the manufacture of incandescent lamps, the operation of raising the carbon filament to incandescence in an atmosphere of coal-gas, for the purpose of hardening and smoothing the carbons, and equalizing their resistance.n. The act of creating an artificial flood in a conduit or stream, as in a sewer for cleansing it, or at shallows in a river by penning up the water either in the river itself or in side reservoirs. See flushing.n. In electricity, on commutators of direct-current dynamo-electric machines, the carrying of a spark from one brush to another, when it appears as a flash encircling the commutator-surface.