I can only speak for US English. When we use "holiday" in the US, we usually refer to an actual holiday...for example: Easter, Fourth of July, Christmas, Memorial Day, Labor Day...
For example:
"Are you traveling anywhere over the holiday weekend?"
"Do you have family coming to town for the holiday?"
"I'm looking forward to the holidays!" <-- maybe said in October, knowing that Thanksgiving, Christmas and New Years are approaching in the months ahead
Otherwise, we use vacation:
"I can't wait for summer vacation!"
"I'm taking a vacation to Mexico next year!"
Again, probably not formal English but if you're looking for a difference in countries, that's my contribution :)
I will personally say "I'm going on holiday next week" just to sound fancy, but it's not common!
"I'm going to holiday in Cape Cod for the summer"
Amazing how a single language gets modified over time based on Geography. It's fascinating to me!