Helen just left a comment bringing up the fact that Happy Holiday comes from the the original "Happy Holy Day." So, it's not a secular greeting, in fact. Also, I've often used it to encompass several holidays at once, like Thanksgiving, Christmas, and New Years. I have also used it when sending out cards to people that may include Jewish people who are celebrating Hanukkah. There's nothing terribly wrong with saying "Happy Holidays" contrary to what my earlier post says. It was an email a friend sent me, and is talking about when it becomes against the law to say "Merry Christmas."