What is "sustainable"?

Thanks to Chad Cook for this one.
The result of an interesting exercise by the folks at http://aquadoc.typepad.com/waterwired/ ,gathering together all the definitions of sustainable/sustainability, explained, here: http://aquadoc.typepad.com/waterwired/2012/02/struggling-to-define-sustainability-try-one-of-these-64-more-or-less-.html

The result:
http://aquadoc.typepad.com/files/sustainability_definitions.pdf