A sustainable building, or green building is an outcome of a design which focuses on increasing the efficiency of resource use - energy, water, and materials - while reducing building impacts on human health and the environment during the building's lifecycle, through better sitting, design, construction, operation, main
"Green building is the practice of increasing the efficiency with which buildings use resources -- energy, water, and materials -- while reducing building impacts on human health and the environment, through better siting, design, construction, operation, maintenance, and removal -- the complete building life cycle." (via Business Exchange)
That's one of the most clear, compact and intelligent summaries I've seen in a while!
Peter Busby explains the keys to green building (Forbes.com)