The definition of industrial ecology

Maybe this blog can come up with a good definition of industrial ecology.

First, let's agree on some principles of a definition here.
1. A definition should be clear and unambiguous. Thus "the science of sustainablity" is not a good definition, because it introduces this nasty and vague term sustainability.
2. A definition should at the same time be open enough to accommodate unorthodox methods and analyses. Thus, a term like "quantitative" should not be part of it, as it would rule out all non-quantitative approaches.
3. IE is primarily a science, a field of research. In that way, it is similar to ecology, economics, astronomy or history. Next to it, people may connect it with strategies, but this should not be part of the definition. When economics is "the study of the choices people make to cope with scarcity", there is no mentioning of using economic theory to become rich. Thus, IE should not be defined as "the shifting of industrial process from open loop systems, in which resource and capital investments move through the system to become waste, to a closed loop system where wastes become inputs for new processes" (Wikipedia), just becauses it mixes up theory and action.
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Other principles will come in an interaction. Shall we agree to discuss principles by way of such enumerated points?

Then, back to IE. As always, ecology provides a useful analogue here. Three useful definitions on the web for ecology are
a) The science of the relationships between organisms and their environments
b) The study of the relationship between plants and animals (including humans) and their environment
c) The study of how organisms interact with each other and their physical environment.
Each of these three can be easily changed to fit IE:
a) The science of the relationships between industrial activities and their environments
b) The study of the relationship between economic actors (including humans) and their environment
c) The study of how industries interact with each other and their physical environment.

I would appreciate to get some comments on these trials.