Presidential Transition: The process of transferring executive power and duties from the outgoing President to the incoming President, which occurs between the general election and Inauguration Day.
Electoral College:The group of electors who formally elect the President and Vice President of the United States, with each state's number of electors equal to its total number of Senators and Representatives in Congress.
20th Amendment: The constitutional amendment that moved the date of Inauguration Day from March 4th to January 20th, shortening the transition period between the election and the new president taking office.