Pro tempore , abbreviated pro tem or p.t., is a Latin phrase which best translates to "for the time being" in English. This phrase is often used to describe a person who acts as a locum tenens (placeholder) in the absence of a superior, such as the President pro tempore of the United States Senate, who acts in place of the President of the United States Senate, a position that is held by the Vice President of the United States ex officio throughout their entire term.
Legislative bodies can have one or more pro tempore for the presiding officer. These positions ostensibly go to legislators experienced in floor debate who are familiar with the content and application of relevant rules and precedents and who have a reputation for fairness among their colleagues.
A common use of pro tempore in the United States is in municipalities such as cities and towns with regard to the position of the mayor. Some cities do not have a position of vice mayor, but rather appoint a person from the city council to act as mayor pro tempore (pro tem) in the absence of the actual mayor.