So I've heard different things regarding this. My PhD is a science based PhD, by the way. I've been told by some people that a PhD is one big study with the result being a new result in a new area. Other people have said that it's essentially 3 small contributions to an area. What's the real answer here?

I'm being told to make a minor contribution for a paper but aren't all research papers novel in a way? Clearly that's not enough for a PhD. So is a PhD a massive research paper or a combination of the smaller ones? If it's a combination of the smaller ones than surely there must be some acceptance for difference in what each contribution achieves? But this is then confusing as all the PhD titles I've seen are like "Doing X with Y" which indicates one contribution.

I'm really confused and worried about this and want to get my understanding right so any advice is greatly appreciated!

It totally varies. My PhD was three distinct chapters with little overlap, all of which are publishable (I hope!) papers. Other friends of mine have PhDs where each chapter is consecutive and they will probably only have 1 paper (but probably better quality than my three).

It could be that your whole PhD is just one minor contribution to a paper. Or it could be no contribution to a paper at all, but just a contribution to the field that you have never published. Or everything you tried to do failed, so your only contribution is a negative result - might not get you a paper, but it will still get you a PhD.

I wouldn't worry too much about thesis titles. My supervisors made me change mine at the last minute to something more specific from my previously generic one and I hate it... but I guess it does better reflect the thesis content.

I agree with TreeofLife, it varies and you shouldn't worry, as long as you have some contribution. I am also under the category where I can get 3/4 publications out because the three studies I have done are linked together but are distinct.