The word so is a very useful word. It can be used in a number of ways. Let us illustrate with a few examples.
It is often used as an adverb and modifies both adjectives and adverbs. In the sentence She is so good, the word modifies the adjective good. However, in the sentence She sings so well, it modifies the adverb well.
The word so can be used as a discourse marker. It can be used to summarize information as in the sentence So, the meeting will be moved to next week. However, it can also signal a change of topic such as So, what do you do?
Another meaning of the word so is also. This is illustrated in the sentence I love tennis and so does my brother. However, the word order is different. With the word also, the sentence is I love tennis and my brother does also.
The word so can also be placed after verbs and replace clauses. For example, to answer the question "Can he come?", it is possible to answer with "I hope so". The sentence "I hope so" expresses the idea "I hope that he can come". Here it replaces the subordinate clause "that he can come".
In many sentences so functions as a conjunction. This is the case in the sentence She isn't feeling well, so she can't come today. The word so connects two independent clauses and is thus a coordinating conjunction.
Though so is a small word, it is very common and has many meanings. It can modify both adjectives and adverbs, function as a discourse marker, express the meaning of also, function as a conjunction that connects independent clauses and follow verbs with the function of replacing clauses. The word so has many uses in English.
