Here are a few different definitions of an ecovillage. I consider these definitions to be among the best available, written by leaders in the movement.

Ecovillages need to be well planned and guided by strong wellness and ecological values. I don't think we can afford to water down ecovillage developments with status quo thinking or short term objectives. Ecovillages need to have the long term interests of the occupants totally in mind and cannot take "developer" interests first.
-Paul J. Belanger

The terms "ecovillage" and "sustainable community" can be used interchangeably. The problem with "sustainable community" is that it has been abused and sequestered by interests which have not completely respected nature or the occupants of the development. Without understanding the key principals which create an actual sustainable community, future residents are at risk of being fooled into something other than what they were lead to believe. For this reason a clear and comprehensive definition of "ecovillage" is critical.
-Paul J. Belanger

WHAT IS AN ECOVILLAGE?

An ecovillage is a human-scale sustainable neighborhood in which economic, social and physical systems are integrated for high quality low impact living. This means that housing-along with livelihood, recreational and civic activities -are all integrated in a self-defined community within walking or bicycling distance. People live close to where much of their food is grown. The physical, economic, and social environment is arranged in a way that encourages quality time with family, friends and neighbors. An ecovillage strives to use natural resources at the pace at which they can be restored.
-Lois Arkin, LA ecovillage

The above definition was written in the early 1990's. In light of the growing global food and water problems stronger words can be added to supplement this well worded definition. This below statement, with implications for food security, community safety and long term settlement viability is particularly relevant for 3rd world villages and new urban development.

Through the use of eco-techonolgy an ecovillage self-manages the basic essentials of life including food, water, shelter and energy. This skilled community creates a safe and a very secure place to live. A sense of control in this self reliant social "module" also eliminates isolation. The residents have regular opportunity to engage in decision making and have more time to interact with society at large.
Paul J. Belanger, July 2008

An ecovillage is human scale, has mixed land uses, strives to close the waste to resource loops, supports healthy human development, has multiple centers of initiative, and can be successfully continued into the indefinite future. -Robert Gilman

An ecovillage is a human scale neighborhood where people know their neighbors and care about them. People can live close to where they work and play and have access to other essential services without use of automobiles. Together, neighbors try to minimize waste and pollution of all kinds. Residents and friends work together to create a healthy community socially, physically and economically. - LAEV Brochure

For more information we have a comprehensive ecovillages section on our links page.