W2 positions at the universities of applied sciences in Germany
The definition is left intentionally vague, in my opinion, so as to not further reduce the pool of applicants unnecessarily. 

The general idea, I believe, is to show that you have cooperation with (and possibly support from) industry. So a BMBF-funded project with an industrial partner is just as viable as a project whose funding comes directly from industry. I think even if neither of those holds, but you have an industrial partner on a project—perhaps seen through joint publications—you could make the case of industrial cooperation.