The adverb hence has a few meanings, including (1) for this reason, (2) from this source, (3) from now, (4) from that time, and (5) from this place. It once functioned as a noun in the phrase from hence, but in modern English that redundancy has fallen out of favor.
Examples
In these examples, hence is synonymous with therefore:
It’s that India has an airline that is run by politicians and hence can be milked by various interest groups. [Wall Street Journal]
The Orthodox Church is surely a form of organised religion; hence his real quarrel is not so much with religion per se, any more than with atheism per se. [Financial Times]
In these sentences, hence means from this source:
Neither of these policies are popular, hence the temptation to resort to printing money (or “monetizing the debt”) to pay its bills. [National Review Online]
This is a species of shorebird that appears to resemble plovers (hence its name), but its relationships are confusing and still being investigated. [The Guardian]
They get married next month, hence the new lot of stepchildren. [New Zealand Herald]
And here, hence means from now or from that time:
Should Britain end up out of the union, some years hence, historians may look back at two events of the present. [The Economist]
But five centuries hence, are the roles about to be reversed? [Scotsman]