The term ecology may be defined in the following ways –

1. Ecology is that branch of biology which deals with the relations and interactions between the organisms and their environment.

2. It is the set of relationships existing between any complex system and its environment.

3. Human Ecology is that branch of sociology which is concerned with the interdependence of people and institutions.

4. It is the study of relationships between human groups and their physical environment.

5. Human Ecology is an interdisciplinary and transdisciplinary study of the relationship between humans and their environment. Here environment includes the natural environment, social environment, and built environment