There isn't any difference. School breaks tend [in the UK] to be called 'holidays'; there are summer holidays, Christmas holidays, and also Easter holidays, in late March or early April. Adults have a holiday from work, take a holiday or go (somewhere) on holiday.

Note that this use of ‘holidays’ is British English. In the US, ‘holidays’ generally refers to a time period. We use ‘vacation’ to describe the trip.

a holiday = festival holidays = summer/ winter/spring holidays, meaning free weeks for schoolchildren

I'd use HOLIDAY for a specific holiday: "My holiday in Jamaica was amazing." Or maybe for a general comment like, "I need a holiday!" If I didn't need to be specific, well, then I'd probably say HOLIDAYS. It covers a number of holidays, or a period of time such as the summer holiday/free time away from school etc. "The summer holidays are great!" probably refers to the time you are free and COULD go ON HOLIDAY if you want. Or you could just sit in your garden! BUT be careful, because "The summer holidays" could be a plural, as in - The summer holidays we have in Greece are wonderful. We go for a two-week holiday every July. Confusing? Yes, it can be. So, if in doubt, ASK someone to clarify what they mean. Have a look at this > "During the summer holidays I go on holiday!" (one holiday). > During the summer holidays I go on holidays!" (more than one holiday)

Oh, you can usethem interchangeably in this type of context.