Verevan was the word used by the Dascarians to describe love of the land. When a piece of land was in dispute or up for sale, a test was given to measure which buyer had the greatest verevan.
The First Doctor bought a parcel of land from Aulian Thorolis' great-grandfather. He passed the verevan test because of his desire to protect the People of the Trees, who lived in the land. Decades later, Aulian resorted to murder to try to regain her family land, but the Fourth Doctor once again passed the verevan test, keeping possession of the land. (PROSE: People of the Trees)