President is a common title for the head of state in most republics. The president of a nation is, generally speaking, the head of the government and the fundamental leader of the country or the ceremonial head of state.
The functions exercised by a president vary according to the form of government. In parliamentary republics, they are usually, but not always, limited to those of the head of state and are thus largely ceremonial. In presidential, selected parliamentary (e.g. Botswana and South Africa), and semi-presidential republics, the role of the president is more prominent, encompassing also (in most cases) the functions of the head of government. In authoritarian regimes, a dictator or leader of a one-party state may also be called a president.
The titles "Mr. President" and Madam President may apply to a person holding the title of president or presiding over certain other governmental bodies. "Mr. President" has subsequently been used by governments to refer to their heads of state. It is the conventional translation of non-English titles such as Monsieur le Président for the president of the French Republic. It also has a long history of usage as the title of the presiding officers of legislative and judicial bodies. The speaker of the House of Commons of Canada is addressed as président de la Chambre des communes in French and as Mr. Speaker in English.
The 1787 Constitution of the United States did not specify the manner of address for the president. When George Washington was sworn in as the first president of the United States on April 30, 1789, however, the administering of the oath of office ended with the proclamation: "Long live George Washington, President of the United States." No title other than the name of the office of the executive was officially used at the inauguration. The question of a presidential title was being debated in Congress at the time, however, having become official legislative business with Richard Henry Lee's motion of April 23, 1789.