1. A product that has just those features that allow the product to be deployed, and no more. 2. The simplest experiment you can run to validate the current most-important customer hypothesis. Or as the Lean Startup community says, the simplest thing you can do, with the least effort, to collect the maximum amount of validated learning about the customer. Synonymous with MVP. See also blog posting “MVP and MMF and MRF, Oh My!”.