A shed is typically a simple, single-story roofed structure, often used for storage, for hobbies, or as a workshop, and typically serving as outbuilding, such as in a back garden or on an allotment. Sheds vary considerably in their size and complexity of construction, from simple open-sided ones designed to cover bicycles or garden items to large wood-framed structures with shingled roofs, windows, and electrical outlets. Sheds used on farms or in the industry can be large structures. The main types of shed construction are metal sheathing over a metal frame, plastic sheathing and frame, all-wood construction, and vinyl-sided sheds built over a wooden frame. Small sheds may include a wooden or plastic floor, while more permanent ones may be built on a concrete pad or foundation. Sheds may be lockable to deter theft or entry by children, domestic animals, wildlife, etc.

An outbuilding, sometimes called an accessory building or a dependency, is a building that is part of a residential or agricultural complex but detached from the main sleeping and eating areas. Outbuildings are generally used for some practical purpose, rather than decoration or purely for leisure. This article is limited to buildings that would typically serve one property, separate from community-scale structures such as gristmills, water towers, fire towers, or parish granaries. Outbuildings are typically detached from the main structure, so places like wine cellars, root cellars and cheese caves may or may not be termed outbuildings depending on their placement. A buttery, on the other hand, is never an outbuilding because by definition is it is integrated into the main structure.