0 a building that has been made in a way that does not harm the environment, for example because it is made with sustainable materials (= ones that will continue to be available and not all be used up) and uses natural energy for heat, etc.:
Eco-buildings come in many different forms.
1 the activity of making buildings that do not harm the environment:
Most of the structures will be built by volunteers who want to learn the art of eco-building.
