For example, in a republic with a presidential system of government, the presidency is the executive branch of government, and is personified by a single elected man or woman who holds the office of "president". In practice, it includes a much larger collective of people, such as chiefs of staff, advisors and other bureaucrats.
The term is also sometimes used to describe the time period in office held by an individual president. For example, the presidency of Richard Nixon overlapped many important developments.
Other states and organizations may have other systems, such as a collective presidency. The presidency of the European Union is held on a rotating basis by the various national governments of the member states. The presidency of British crown colonies is held by the office of the United Kingdom colonial secretary.
The presidency may also refer to the holder of a non-governmental office of president in a corporation, business, charity, university, etc or to the institutional arrangement around them. For example "the presidency of the Red Cross refused to support his idea."