International Dark Sky Community (IDSC): A town, city or any other legally formed  municipality having shown evidence of exceptional commitment to preservation of  the night sky.  Essential activities  include implantation and application of regulations on exterior lighting as  well as public education on the importance of a dark sky.

International Dark Sky Park (IDSP): A protected public land, such as a park, having a  night sky of exceptional quality as well as a nocturnal environment lacking  light pollution.  Natural darkness within  the area must be considered of prime importance for cultural, esthetic and  educational reasons.

International Dark  Sky Reserve (IDSR): A public or private land that offers an exceptional quality of the  nocturnal environment and the night sky.   This extensive tract of land is protected for its scientific, natural,  educational and cultural heritage and/ or for its mission to offer a vast  territory for public enjoyment.  An IDSR  is composed of a central region that fulfills the minimum criteria for natural  darkness, as well as a peripheral region that supports and benefits from a dark  sky in the central region.  The IDSR is  thus based on a partnership between the different property owners and/ or  administrators in the territory who publicly recognize the value of the night  sky through regulations, formal agreements and long-term planning.