mill that manufactures black powder (type of gunpowder)

Rumor mill.

plural of pug mill

A kind of mill for grinding and mixing clay, either for art or brickmaking. 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.

A device that grinds material very finely by means of a horizontally rotating drum containing ceramic or metal balls

Alternative form of millwheel

Alternative form of millstream

plural of mill wheel

(informal) Romantic in a formulaic way.

plural of Mills bomb