The term 'kind of mill' can refer to several different types of mills. Treadmill is a kind of mill that is used for exercise, and is powered by the user's own movement. RUMOR mill is a kind of mill that refers to the spread of gossip or rumors. GRIST mill is a kind of mill that grinds grain into flour. GIN mill is a kind of mill that produces GIN, a type of distilled alcoholic beverage. DIVORCE mill is a kind of mill that refers to a lawyer or law firm that handles a large number of DIVORCE cases.