Hero-stones (a.k.a. Mahasati stones or Veeragals) are carved stones erected in the honor of a brave man or woman who perished while defending the interests of the village (such as while fighting bandits who attempted to steal cattle, or invaders who abused women).
Sati-stones (also sometimes called Mahasati-stones) are stones erected in the honor of wives who committed suicide after their husband's untimely death. The glorification of the Sati practice is typically found on these stones.
Nishidhi-stones are pillars or stones erected in the memory of those who died in the course of Sallekhana. Sallekhana, or the "death-inviting" practice, was performed by devout Jains who meditated and starved until death.