Dictatorship is form of government in which one person or a small group possesses absolute power without effective constitutional limitations.
When Hitler was appointed in January 1933, Germany was a democracy. Germany had fair elections; nobody had their right to vote abused; there were numerous political parties to choose from at voting time. To pass a law, the Reichstag had to agree to it after a bill went through the normal processes of discussion and debate.
Hitler had promised a general election for March 1933. One week before the election was due to take place, the Reichstag building burned down. Hitler knew that if he was to convince President Hindenburg to give him emergency powers - as stated in the Weimar Constitution - he had to play on the old president's fear of communism. What better than to convince him that the communists were about to take over the nation by force?
Unsurprisingly, a convenient patsy, and known Communist supporter - Marianus van der Lubbe - was caught near the Reichstag building immediately after the fire started. Those that arrested him - Nazi officials - claimed that Lubbe confessed that the fire was a signal to other communists to start the revolution. Matches were allegedly found on van der Lubbe and those who arrested him claimed that he smelt of petrol.
Hmmm, how convenient.
Hitler asked Hindenburg to grant him emergency powers in view of the 'communist takeover'. Using the constitution, Hindenburg agreed to pass the Law for the Protection of the People and the State. In the months and years thereafter, Hitler steadily introduced law after law, which gradually turned Germany into a Dictatorship.
Exactly the same process commenced on September 11, 2001 in the USA, and concluded with the inclusion of law HR6166 into the American Constitution on the Sept 28, 2006.