Inauguration Day

from the GNU version of the Collaborative International Dictionary of English.

• The day on which the President of the United States is inaugurated, the 20th of January in every year next after a year divisible by four. Prior to the adoption of the twentieth amendment to the Constitution of the United States (ratified February 6, 1933) the date was the 4th of March.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• proper noun The day on which a President and a Vice-President of the United States takes office, now on January 20 after a Presidential election, before 1936 on March 4.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the day designated for inauguration of the United States President