C anniversary annual holiday bicentenary biennial birthday bissextile day cental centare centenarian centenary centennial centennium centigram centimeter centipede centistere centred centref centrev centumvir centumvirate centurion century commemoration cwt decennial diamond jubilee golden wedding anniversary gross hecatomb holy days hundred hundredweight immovable feast jubilee leap year long hundred name day natal day octennial one C quadrennial quasquicentennial quincentenary quincentennial quinquennial septennial sesquicentenary sesquicentennial sextennial silver wedding anniversary tercentenary tercentennial tricennial triennial wedding anniversary