'A week holiday' is incorrect. You cannot put the two nouns 'week' and 'holiday' together in this way. When you're talking about a period which lasts a certain time, you need to use the 's form. Here are some similar examples with 'a week', mainly to do with employment: A week's rest A week's leave A week's absence A week's notice The length of time can also be a plural noun, if you are talking about a period of two weeks, for example. In these cases, the apostrophe comes after the s: Two weeks' holiday Three days' leave Six months' notice The other alternative, as some members have suggested, is to make an hyphenated adjective: A week's holiday = a week-long holiday Two weeks' holiday = a two-week holiday I hope that's clearer now.

Both are correct and have the same meaning. Useful reference: English Grammar in Use, 5th ed., by Murphy. Unit 81 I've got a week's holiday starting on Monday. Julia has got three weeks' holiday I live near the station - it's only ten minutes'walk. Unit 80 a four-week course [not a four weeks course]

Neither sounds right to me. It would be better to say something like "I have a week off for the holiday"

These can mean different things when speaking because, as Ons said, weak and week sound the same. If you told me that you "just had a week's holiday", I would think you had just spent a week off work / on vacation. If you told me you had "just had a week holiday" I would think that you had been on holiday and it hadn't been very good (weak).

Neither REALLY make sense, but both are ok by me. I've never thought about punctuating this. Maybe better to leave it to spoken English, because it does break down when you try to make sense of it. I definitely would say it as a week's holiday, even though the holiday doesn't belong to the week. A week-long holiday actually makes sense. A week holiday works for me, but don't make it a weak holiday!