Testing the initial appeal and actual usage of a potential new product by simulating its core experience with the smallest possible investment of time and money.
Cheaply test your thinking “build it, and they will come.” Learn from it as fast as possible. Think 1 PowerPoint slide, single page website, $100 AdWords campaign, product packiging/logo… search Pretotyping for examples.
I think of pretotyping as minimum-viable MPV ie MVMVP. Does sound like an acronym hell but you what I mean.