1. (n.) The day in which any person is born; day of origin or commencement.

2. (n.) The day of the month in which a person was born, in whatever succeeding year it may recur; the anniversary of one's birth.

3. (a.) of or pertaining to the day of birth, or its anniversary; as, birthday gifts or festivities.

anniversary annual holiday bicentenary bicentennial biennial bissextile day centenary centennial commemoration decennial diamond jubilee golden wedding anniversary holy days immovable feast jubilee leap year name day natal day octennial quadrennial quasquicentennial quincentenary quincentennial quinquennial septennial sesquicentennial sextennial silver wedding anniversary tercentenary tercentennial tricennial triennial wedding anniversary