‘Definitions and ancestors’ looks back at the history of the concept of anarchy from the end of the French Revolution to the present day. ‘Anarchy’ comes from the Greek anarkhia, which means without a ruler, or contrary to authority. It was used as a derogatory term until 1849 when Pierre-Joseph Proudhorn used it to describe his political and social ideology. He argued that organization without government was both possible and desirable. For anarchists the state is the enemy and they have applied this interpretation to the outcome of every revolution of the last two hundred years. What do the various strands within the blanket term ‘anarchism’ stand for?