season's greeting?

It is the custom, in the English-speaking world at least, to send greetings or good wishes at certain times (seasons) of the year, chiefly Christmastime and New Year.

So if someone sends you "Season's Greetings", they are saying "A Merry Christmas and a Happy New Year".

Note, that is for written messages only. Speaking to someone directly, you would either wish them Merry Christmas or Happy New Year, as appropriate.

Also, Season's Greetings could be used by people who are not convinced about the value of Christmas....but it is not spoken, only written, in a Christmas card or suchlike.

Early sightings of festive felicitations are always a good sign.

True. But I was just answering this question.

The time around midwinter is sometimes known as "the season of goodwill"

Deck the halls with boughs of holly
'Tis the season to be jolly....

I think the purpose of the season's greeting is to take care of everyone who is celebrating something in December, be it Christmas, Kwanzaa, Hanukkah, or whatever else. It generally includes New Year's Day, too. I've known a few athiests who put up a Christmas tree because it's fun to decorate and celebrate, even if you are not celebrating Christ's birth.

By greeting someone this way, the intent is to not offend someone who may be celebrating something different than Hanukkah, Christmas, or what have you. But of course, using this greeting almost always does offend someone with strong beliefs.

My philosophy is to give Christmas cards to those who celebrate Christmas, Kwanzaa to those celebrating that, and Hannukah cards to those of the Jewish faith. If you aren't sure, then take a risk and send the "Season's Greetings", or better yet, risk offending them by sending them a card with what you are celebrating.

Companies often send out Season's Greetings to clients/employees so as to not offend anyone.