What is the "witch's mark" in the novel, Weyward?

The witch’s mark is a symbol of wrongdoing. In Altha’s time, women who had a mole anywhere on their bodies were believed to be witches. These moles were called withes’ marks and were seen as indisputable proof the woman practiced witchcraft. Altha, her mother, Kate, Violet, and Elizabeth all had moles and would have been condemned as witches. Altha was not condemned only because she scratched her mole off, leaving a wound that appeared to be just an insect bite.