A building: Lärbro church at Gotland, Sweden

Building is either the act of creating an object assembled from more than one element, or the object itself. A building is usually a human-created object composed of more than a single element, permanently fixed to the ground, that mediates one or more aspects of the environment.

Buildings may be as simple as a lone roof providing shelter from the rain for a single occupant, or as complex as a hospital regulating temperature, air flow, light, gas content, bacteria movement, particle flow, pressure, and people movement and activities.

The design construction and operation of buildings is as old as humankind. Architects today design most large-scale buildings in a team with a large number of specialized engineers. Small residential buildings do not usually involve extensive work by architects or engineers.

Systems for transport of people within buildings:

Systems for interconnecting buildings: See also:
Building can also refer to the act of assembling a computer program from one or more source files. In which case, like a building, the foundation must be laid. The foundations necessary in building a program are the compiler, and other dependency all spelled out in list files, and makefiles. On Windows and Mac OS Classic, you always need to obtain a compiler since those operating systems don't include one. In addition, when compiling Unix programs, or if you are interested in running a Unix environment or an environment with mostly open source software, people frequently require or recommend cygwin. While the difference doesn't really matter, building refers to the whole process of preparing a source to be run, wheras compiling is a step in the process.