To begin with, I point you to a passage as quoted by the website "ThinkProgress" that has an article discussing what being progressive means:
Everyone gets a fair shot, everyone does his or her fair share, and everyone plays by the same rules. As progressives, we believe that everyone deserves a fair shot at a decent, fulfilling, and economically secure life. We believe that everyone should do his or her fair share to build this life through education and hard work and through active participation in public life.
That is taken from a collective document titled Progressive Thinking: A Synthesis of Progressive Values, Beliefs, and Positions.
Let me know of you would like to hear more about what the definition of a progressive is.
