This can be interpreted differently depending on the country that you are in. In the USA: Holiday: A break for a celebration either national or religious. For example, in American The fourth of July is a national Holiday Vacation: a break that you take somewhere else. You can go to a different place. In the UK: Holiday can be used for vacation. Vacation isn't used that much in the UK

It's actually the same thing from my understanding. I'm on holiday = I'm on break. Vacation = On break, but spending it elsewhere. That's what I think, although for the most part they should/do mean the same thing to me.

In the US, a holiday lasts just one day and a vacation can last a longer period of time. The word "vacation" doesn't exist in British and Australian English, except as the noun form of "to vacate". "Holiday" covers both definitions.

A holiday is usually a day of national celebration. For example: In Germany, the third of October is a national holiday because that's the day of German unity. We celebrate that our country reunited. That's why we usually don't go to work that day. Christmas Day is another holiday. A vacation is time that you take off from work yourself. For example: You could take a month off this year and then travel to Spain during that time to stay at the beach and relax. If you do that then you "go on vacation".

A holiday is usually celebrated by the country or by a religious group while a vacation is personal or family time taken off.