If you're trying to be politically correct, you should say "Happy Holidays" because this includes holidays and festivities of all religions from Hanukkah to Christmas to Kwanzaa. If you just want to know the correct term for Merry Christmas (ie. Is it Merry Christmas? Happy Christmas?), then Merry Christmas is correct.
Just as in your question !They tend to say "Happy Christmas" instead of "Merry".Merry Christmas
You say "Happy Holidays". If the person is Christian you can say "Merry Christmas", if the person is Jewish you can say "Happy Hanukkah" or if the person is African you can say "Happy Kwanzaa"
You say ' Merry Christmas' in the UK.
merry christmas
"Merry Christmas"
merry christmas
Merry christmas
Merry Christmas
merry Christmas= Christmas aashamsakal
Hanukkah is a holiday, not a language. You cannot say "Merry Christmas in Hanukkah. That's like asking: "How do you say Merry Christmas in Easter" I think he means how do you say merry Christmas in Hebrew
Merry Christmas