What does "flatting" mean?

Additional senses

1. 2.A method of preserving gilding unburnished, by touching with size. Knolles.
2. 3.The process of forming metal into sheets by passing it between rolls. Flatting coat, a coat of paint so put on as to have no gloss. -- Flatting furnace. Same as Flattening oven, under Flatten. -- Flatting mill. (a) A rolling mill producing sheet metal; esp., in mints, the ribbon from which the planchets are punched. (b) A mill in which grains of metal are flatted by steel rolls, and reduced to metallic dust, used for purposes of ornamentation.