1. used in negative statement to describe a situation that has existed up to this point or up to the present time
e.g. So far he hasn't called
the sun isn't up yet
Synonym: thus farup to nowhithertoheretoforeas yetyettil nowuntil now
2. used after a superlative
e.g. this is the best so far
the largest drug bust yet
Synonym: yet
3. to the degree or extent that
e.g. insofar as it can be ascertained, the horse lung is comparable to that of man
so far as it is reasonably practical he should practice restraint