The smock mill is a type of windmill that consists of a sloping, horizontally weatherboarded, thatched, or shingled tower, usually with six or eight sides. It is topped with a roof or cap that rotates to bring the sails into the wind. This type of windmill got its name from its resemblance to smocks worn by farmers in an earlier period.

A windmill is a structure that converts wind power into rotational energy using vanes called sails or blades, by tradition specifically to mill grain (gristmills), but in some parts of the English-speaking world, the term has also been extended to encompass windpumps, wind turbines, and other applications. The term wind engine is also sometimes used to describe such devices.