Darshanas are schools of philosophy based on the Vedas. They are part of the six scriptures of the Hindus, the other five being Shrutis, Smritis, Itihasas, Puranas, and Agamas.
This page shows two charts—one with the structure of the Darshanas, and the other showing the essence of the Shad-Dharshanas, which are the Six Systems of Hindu Philosophy.