Joseph Stalin was a dictator, meaning that he seized all power in Russia for himself; he was the sole ruler of the entire country, which meant he didn't have to rely on anyone but himself for counsel. He was considered a tyrant because his rule was a reign of terror - he led to millions of his own people dying just because he wanted to achieve his own goals. He mercilessly executed people who disobeyed him, exiled many, and sent them to labor camps.