I usually call it Christmas Eve Eve.

shopping, cooking, baking, planning, gift wrapping, housecleaning, decorating, hosting of family,etc. I think the day after Christmas should be called Chill Out Day.

More patriarchal crap, imo.

Irish tradition when men take care of house and kids, women have a day out with sherry and cakes.

What do they call it?

What Mom has to deal with the rest of the year as he takes care the house and kids for her on her one holiday.
Ya, right.

Haele

The evening before is Twelfth Night, the day before is the twelfth day of Xmas. (More know that name as the name of a Shakespeare play, I think, these days, than as a blip on the Anglican church calendar.)

"Xmas Adam" is a nifty name for what I would have thought of as the preparation day for Xmas eve. My family did everything on Xmas eve for Xmas, right down to the decorations (inside and out), baking, etc. My godparents, on the other hand, had Xmas Eve mass or Xmas mass and really leaned into Xmas eve. For Irene, godmother, the day before Xmas eve was largely a preparation day for Xmas eve so she'd hit the dinner and whatever not exhausted and beleaguered. Or maybe just mis-schedule a lot of things so that preparations weren't actually done with their close family guests arrived.

"Xmas eve preparation day" lacks the sort of ring that makes it a useful term, it doesn't roll off the tongue. While the one complained about isn't a term I've heard before, but it sounds useful if you really make Xmas a big deal. And I can see churches scrambling for parishioners of any sex since Xmas seems to be commercialized and who wants to go to a buzz-kill church service on Xmas?

(NULL-ug nah mon)
https://www.rte.ie/brainstorm/2024/0106/1103975-nollaig-na-mban-january-6th-ireland-roots-traditions-customs/