That...

[Volcano1985]

However,he missed the Dorset countryside so much that he returned there in 1867 and began writing novels and poetry.

what does "that" mean here ?

[Fazzu]

Here it just expresses how much he has missed the Dorset countryside.

Perhaps,'that' means 'again' in this case.

Hope I'm right.

[Volcano1985]

i thought so too but i wasn't sure.I think it might be "so...that" meaning there.

[Fazzu]

He missed the Dorset countryside so (that) did he returned again to see it.

I hope you are right there too, Volcano.

[Irushka]

I think "that" means "that's why" he returned

[Volcano1985]

Or It may explain "so much" meaning here.

He missed so much that.....

so much=this yearning forced him to came back in 1867 and continued his life there.

[Teia]

However,he missed the Dorset countryside so much that he returned there in 1867 and began writing novels and poetry.
what does "that" mean here ?

For a better understanding I`d rephrase your sentence :

"However, he missed to such an extent/so much the Dorset countryside ,that[conjunction] he returned there in 1867..."

Regards,

[Fazzu]

I think "that" means "that's why" he returned

You are right too.He missed Dorset countryside 'that was why' he went back there again.

For a better understanding I`d rephrase your sentence :

"However, he missed to such an extent/so much the Dorset countryside ,that[conjunction] he returned there in 1867..."

Regards,

So, Teia what do you think 'that' means here besides it is a conjunction?

[Teia]

You are right too.He missed Dorset countryside 'that was why' he went back there again.
So, Teia what do you think 'that' means here besides it is a conjunction?

Hi Fazzu

I think your interpretation is right :"that was why" /that was the reason why....

Regards,

[DavyBCN]

However,he missed the Dorset countryside so much that he returned there in 1867 and began writing novels and poetry.
what does "that" mean here ?

While I agree with the different possible meanings of that which people have posted, I think Teia has given the most approriate answer when she says that is used here only as a conjunction between two clauses, and it is a conjunction which is often left out. The original sentence can, and often is, written in this way:-

.....he missed the Dorset countryside so much he returned there in 1867......

English omits that very, very often, unlike some other languages.