Vacation, holiday or holidays???

You use holiday (or holidays) in BrE and vacation in NAmE to describe the regular periods of time when you are not at work or school, or time that you spend travelling or resting away from home:
I get four weeks’ holiday / vacation a year.
He’s on holiday / vacation this week.
I like to take my holiday / vacation in the winter.
The summer holidays / vacation.

In NAmE a holiday (or a public holiday) is a single day when government offices, schools, banks and businesses are closed: The school will be closed Monday because it’s a holiday. This is called a bank holiday in BrE.

The holidays is used in NAmE to refer to the time in late December and early January that includes Christmas, Hanukkah and the New Year.

Vacation in BrE is used mainly to mean one of the periods when universities are officially closed for the students.

Source: Oxford Advanced Learner's Compass