The season or time made up of the twelve days between Christmas and Epiphany; Christmas season, Christmas time, Christmastide, Twelvetide. The Christmas season traditionally ended with the feast of the Epiphany on January 6.

(idiomatic) Some period of time, such as a term of employment or a lifetime, is coming to an end.

plural of red-letter day

A typical bad day.

(Britain, euphemistic) An exclamation of astonishment or gleeful disapproval.

plural of bad hair day

Alternative form of nine day wonder

A bygone era of innocence and simplicity, especially youth

plural of New Year's Day

plural of cold day in Hell