In decision theory and general systems theory, a mindset is a set of assumptions, methods, or notations held by one or more people or groups of people that is so established that it creates a powerful incentive within these people or groups to continue to adopt or accept prior behaviors, choices, or tools. This phenomenon of cognitive bias is also sometimes described as mental inertia, "groupthink", or a "paradigm", and it is often difficult to counteract its effects upon analysis and decision making processes.
On the positive side a mindset can also be seen as incident of a person's Weltanschauung or philosophy of life. For example there has been quite some interest in the typical mindset of an entrepreneur.
Read more about Mindset: Mindsets in Politics, Collective Mindsets