Why would my DIL get so upset over this?

Something from the past, no doubt, that has a strong past-experience charge for her that got triggered by some aspect of it. My guess is it’s any time she has told her child about something, and they seem to her to be doing something like the situation she has a charge about. Not knowing her nor having seen more than what you wrote about it, I couldn’t say, but it’s a pretty common sort of thing for parents to have a hang-up about. It’s often ancestral and passed down from generation to generation.

Kids can be really really really annoying. Is it possible that when he said that, he was being really really really annoying?

She must have a rigid American idea of what “holiday” means (Easter, Thanksgiving, etc.), and so she corrected him. I bet she didn’t get mad until after he ignored her correction. And then you sided with him. I’m guessing it’s not about the word so much but instead about being shown up by a 6-year-old and ganged up on by you. (Did you happen to be the one who read him the book?)

I’m also guessing that the kid enjoyed the power the word had over her. @nikipedia is right, kids are like that.

I hope she doesn’t get into such a snit that it spoils their, uh, recreational trip.

I think it’s adorable, maybe she needs a nice long jump in the lake. haha!
With all the stories you’ve told us over the years she sounds like a nightmare honestly. But I’m glad you’re able to calm her sometimes. Good grandma!

To me it could have been a lesson in other cultures.

She’s a control freak.

I have a neighbor who insisted that clay pigeons for trap and skeet shooting were called “skeets,” that there was no difference between skeet shooting and trap shooting. And he calls his trampoline a “tramp.” Like he wants to create his own little language pool with his children and grandchildren. Does he have no idea of the ridicule his kids face because of his slaughter of the English language??
There are just people like that and nothing can really be done about it.

Perhaps she is aggressively anti-European. And yes, kids can be annoying.

I don’t think European is a culture?

For her, she is on vacation. Thatmeans vacation “rules” apply, like wearing a bathing suit at dinner, less structured eating, maybe a beer or two when shoe wouldn’t have one.

Being on a “holiday“may carry a lot of negatives for her, where the men and kids sit around and she is the only one working, plus having to get dressed up.

@Dutchess_III Taking the kid’s side, and planning to saying something just to annoy your DIL is a lousy way to treat her, and uf I were in her shoes, you would never see her or the kids while they are on vacation again.

I think she didn’t know holiday is synonymous with vacation in some parts of the English speaking world.

Maybe her son has been challenging her a lot lately and she had no patience for it.

Did one of the kids just read a Harry Potter story? They go on holiday at the end of every term at Hogwarts.

That may well have been it!

I started to narrow it down to the UK but then I remembered that in Anne Frank’s biography she mentioned going on holiday at her Grandmother’s every summer. I realized the phrase was much more wide spread than just the UK.

Anne Frank wasn’t writing in English. That would have been the translator’s word choice.

Also it could have come from a movie or TV show. “It’s a jolly holiday with Mary” (Poppins), for instance.

I’m thinking maybe DIL is just really stressed out over something else and this little thing was one little thing too many.

@Dutchess_III Does she drink? Maybe take the kids fishing, leave her wine spritzers and see if she gets happy. Haha!

No. She doesn’t drink thank God. She’s angry and volatile enough with the kids as it is.

Maybe because he has a hard time understanding the difference of what a holiday and a vacation is. For instance. Let’s say on labor day, the school says they won’t be coming in because it’s a holiday. Will he expect a vacation trip? But more than likely it was made clear to him and he simply wanted to be contrary because he knows how to push mom’s buttons. Instead, you should’ve told her he was probably trying to be difficult and if she said fine, you can call it a holiday, but don’t expect a vacation trip every time a holiday comes around, then I bet he would quit.
He also probably knew you would side with him which no doubts pushes moms buttons more.

It’s just a word, and means essentially the same thing. I’d think there are much more serious issues in this country today to get bent out of shape about if one chooses, rather than a child using “holiday” over “vacation”. Sounds to me like this woman has some serious issues of her own. Unrelated to word choice.

Usually a holiday is a celebration of an event, a vacation is just time off from work.
The things you describe are just struggles between parents and children for independence vs control.

@Pandora That’s in American English, in Europe holiday is synonymous with vacation. So, the explanation is not only how we use the word, but as many other jellies said, it’s possible the mother doesn’t understand that the child is correct if he were living in England.

You could be right that the child is mixing it up as you stated, but it also could be right that the kid simply hasn’t separated the two dialects and the mother is ignorant to the different uses of the word in the world.