Adverb
used in negative statement to describe a situation that has existed up to this point or up to the present time
to the degree or extent that
used after a superlative
Source: WordNetIt's better to be unhappy alone than unhappy with someone - so far. Marilyn Monroe
I think computer viruses should count as life ... I think it says something about human nature that the only form of life we have created so far is purely destructive. We've created life in our own image. Stephen Hawking
So far as it depends on the course of this government, our relations of good will and friendship will be sedulously cultivated with all nations. John Tyler
The mountains are never so far apart but the animals find one another. American Proverb
The king goes as far as he can, not so far as he would. Spanish Proverb
The apple falls not so far away from the apple-tree. Russian Proverb