Pug, n.
1. Tempered clay; clay moistened and worked so as to be plastic.
2. A pug mill.
Pug mill, a kind of mill for grinding and mixing clay, either for brickmaking or the fine arts; a clay mill. It consists essentially of an upright shaft armed with projecting knives, which is caused to revolve in a hollow cylinder, tub, or vat, in which the clay is placed.