Not really quite sure exactly what your question is, but yes — 'holidays' implies simply time off work or school, vacations, whereas 'holy days' (the original spelling of the other word, of course) refers to special days that are designated as religious feast (etc.) days in certain religions (from personal experience, the Roman Catholic church, but of course other religions too)

--------------------------------------------------
Note added at 4 days (2008-10-03 08:23:07 GMT) Post-grading
--------------------------------------------------

No, certainly not! I don't know in fact if protestant faiths even have such things, since 'saint-worship' is I believe a less prominent feature of these faiths in general.

Certainly, most of the 'holy days' I can think of would be Roman Catholic ones, and likely carried over into the Church of England — and no, the 'holy' ones would NOT (necessarily) be public holidays; I'm thinking in particular of things like the 'holy days of obligation' which I well remember from my Catholic childhood.

Of course certain more prominent, high-profile holy days are also public holidays, like Easter Monday and Christmas Day (though exactly which ones will differ from country to country, France as a lot more than the UK, for example).