Almost. But then.
In Ireland you go on holidays (or on your holidays), when you go away from home and stay somewhere else for a while. You are on holidays when you don't have to go to school or work for a while. That much translates directly to "vacation", except for the plural.
Holiday, in the singular, is where one might get confused, because Americans use that too.
A holiday in the US is a public day off, such as July 4th or Labor Day. A holiday weekend is the weekend one of these days is attached to. A typical conversation at work when I first moved to America might go like this:
- How was your holiday?
- What holiday? I didn't go anywhere.
- Monday. Was a holiday. Remember?
- Oh, you mean my bank holiday.
- What's a bank holiday?
In the UK/Ireland, a bank holiday is what we generally call a public holiday, and that weekend (when it falls on a Friday or a Monday), is a bank-holiday weekend. Confusingly, there is actually a distinction between bank holidays and public holidays, and sometimes the bank is closed when everyone else has to go to work, but mostly they're all just called bank holidays. Because if the bank is closed, it's time to party. Apparently. (I bet it's Angela Merkel's fault.)
"The holidays", in America, means the Christmas season, which you aren't allowed call Christmas for fear of offending people who celebrate Kwanzaa or Hannukah or Solstice or whatever else it might be. Hence "Happy holidays", which to an Irish person would evoke images of sun-drenched beaches, and fruity libations, possibly in Spain. To an American it means snowflakes and ice-skating and gingerbread cookies and other secular wintery goodnesses.
If in doubt, just call it a break.