An alternative atheistic "holiday" that corresponds with the Christmas season. There are many derivations of celebration, but main themes include satirizing commercialism and religion, eating Athmas burritos, and generally giving atheists and other non-christians a chance to celebrate without giving in to religious nonsense.
Athams is abbreviated "-mas", which represents "christmas without the christ".
Guy1- What did you do over winter vacation?
Guy2- I celebrated Athmas.
Guy1- What's that, like atheist christmas?
Guy2- Sorta, but not really. I ate athmas burritos, decorated my athmas tree, and gave an athmas present to my cat.
Guy1- That sounds awesome! I think I'll celebrate athmas next year, since Jesus never actually existed.