LEED (Leadership in Energy and Environmental Design):  a voluntary, consensus-based national standard for developing high-performance, sustainable buildings.  Only projects can be LEED certified, not the products themselves.

LEED is probably the best known, comprehensive and widely accepted green rating system for a variety of buildings and projects.  The U.S. Green Building Council (USGBC) has developed several different LEED standards that cover different types or phases of construction.  Project design teams are free to choose which credits they wish to apply for.  Depending on the number of points achieved, the project is given a rating of Certified, Silver, Gold or Platinum.

The intent of the LEED standard is to provide design guidelines and a third-party certification tool for green building.  While points or credits are not awarded specifically for using a particular product, many US SPEC products offer features that can be factored into a project's point and credit calculations.