Does "so" have similar usage and meaning in English and German?
so ein schönes Lied!
das tut uns [ja] so leid!
so? Das wäre aber sonderbar
du darfst nehmen, so viel wie du willst.
alles ging so weit (bis dahin) gut, aber dann …
So is one of the most complicated words in German. The Grimm has dozens (if not hundreds) of pages (the link generator is somewhat broken - follow the link, search for "so", and click on the second "so" entry) on this word. "So" can be an adverb, a conjunction or a particle. Most of the uses are the adverb. From the chat:
Some of the meanings are very similar to English. It can mean something similar to "very":
It can also mean a surprise:
In this case, you could also say "Ach so?" or "Tatsächlich?" instead.
An important meaning of "so" in German, however, is a comparison. so-wie is used similar to as-as in English:
It can be used standalone, on the other hand:
In this case, it is still a comparison and kind of requires more explanation (sie stößt mit dem Kopf an die Decke).
In English, "so" is often used like "hence". You can use it in German as well:
"so" can also mean "like this" in German, for example:
The "so" is pronounced rather long - and you show what you mean while saying it. I don't know if it is used like this in English as well.
Note that the verb can be omitted in some variants.
"so" can also mean "einfach so", or describe an omitted previous situation (from Duden):
And it can mean "etwa":
Usages of the conjunction
In the form "so dass":
It can be used conditionally:
Other forms include (from Duden) the concessive use:
And comparing use:
If you still can't get enough of the word "so" in German, read yesterday's chat transcript from here - highlight "so" ;)
In addition to OregonGhost's answer, I can think of the following other uses of "so" (some overlap in meaning):