A COMPLEX is a group of buildings that are connected and form a single entity. It is usually used to refer to a large, organized collection of buildings, such as an apartment COMPLEX or a business park. Complexes are often designed with a specific purpose in mind, such as providing housing or office space. They can also be used for recreational purposes, such as a shopping mall or a theme park. Complexes are typically located in urban areas and are often surrounded by other buildings and amenities.