so

from The American Heritage® Dictionary of the English Language, 5th Edition.

• adverb To the amount or degree expressed or understood; to such an extent.
• adverb To a great extent; to such an evident degree.
• adverb Afterward; then.
• adverb Used to preface a remark or signal a new subject.
• adverb In the same way; likewise.
• adverb Apparently; well, then. Used in expressing astonishment, disapproval, or sarcasm.
• adverb In truth; indeed; assuredly.
• adverb Informal Used as an intensive, especially with verbs or verb phrases.
• adverb In the condition or manner expressed or indicated; thus.
• adjective True; factual.
• adjective In good order.
• conjunction For that reason; therefore.
• conjunction With the result or consequence that.
• conjunction With the purpose that.
• pronoun Such as has already been suggested or specified; the same or roughly the same.
• interjection Used to express surprise or comprehension.
• idiom (so as to) In order to.
• idiom (so that) With the purpose that.
• idiom (so that) With the result or consequence that.
• idiom (so what) Used to express contempt or lack of interest.

from The Century Dictionary.

• noun See soe.
• Go quietly! gently! easy now! be still: often used in quieting a restless animal. Sometimes spelled soh.
• Nautical, a direction to the helmsman to keep the ship steady: as, steady, so! steady!
• An abbreviation of south.
• In, of, or to that degree; to an amount, extent, proportion or intensity specified, implied, or understood: used in various constructions.
• In the same sense so sometimes modifies a verb.
• With an adjective, adverb, or verb only, the consequent being omitted or ignored, and the degree being fixed by previous statements or by the circumstances of the case.
• Followed by that, as, or but, introducing a clause or an infinitive phrase noting result.
• In this sense sometimes followed by a phrase or clause of result without any connective.
• Of or to the following degree, extent, amount, etc.; thus.
• In that manner; in such manner (as the context indicates).
• In the manner explained by a correlative as (or so or how) and a subordinate clause.
• In the following manner; as follows; thus.
• In the manner previously noted or understood.
• Still gath'ring force, it smokes; and, urg'd amain, Whirls, leaps, and thunders down impetuous to the plain;
• In such a manner: followed by that or as, with a clause or phrase of result.
• By this or that means; by virtue of or because of this or that; for that reason; therefore; on those terms or conditions: often with a conjunctive quality (see II.).
• In a like manner, degree, proportion, etc.; correspondingly; likewise: with a correlative clause (usually with as) expressed or understood.
• In such way as aforesaid; in the aforesaid state or condition; the same: a pronominal adverb used especially for the sake of avoiding repetition.
• As aforesaid; precisely as stated; in very truth; in accordance with fact; verily.
• Such being the ease; accordingly; therefore; well, then: used in continuation, with a conjunctive quality.
• In an indefinite degree; extremely: as, you are so kind; we were so delighted.
• Then; thereafter.
• An abbreviation of so be it: implying acquiescence, assent, or approbation.
• An abbreviation of is it so? as, He leaves us to-day. So?
• In asseveration, and frequently with an ellipsis: as, I declare I did not, so help me God!
• As an indefinite particle: Ever; at all: now used only in composition, as in whoso, whosoever, whatsoever, etc.