The Collaborative International Dictionary of English v.0.48:

So \So\, adv. [OE. so, sa, swa, AS. sw[=a]; akin to OFries,
   s[=a], s?, D. zoo, OS. & OHG. s?, G. so, Icel. sv[=a], sv?,
   svo, so, Sw. s?, Dan. saa, Goth. swa so, sw? as; cf. L. suus
   one's own, Skr. sva one's own, one's self. [root]192. Cf. As,
   Custom, Ethic, Idiom, Such.]
   1. In that manner or degree; as, indicated (in any way), or
      as implied, or as supposed to be known.
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            Why is his chariot so long in coming? --Judges v.
                                                  28.
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   2. In like manner or degree; in the same way; thus; for like
      reason; whith equal reason; -- used correlatively,
      following as, to denote comparison or resemblance;
      sometimes, also, following inasmuch as.
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            As a war should be undertaken upon a just motive, so
            a prince ought to consider the condition he is in.
                                                  --Swift.
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   3. In such manner; to such degree; -- used correlatively with
      as or that following; as, he was so fortunate as to
      escape.
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            I viewed in may mind, so far as I was able, the
            beginning and progress of a rising world. --T.
                                                  Burnet.
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            He is very much in Sir Roger's esteem, so that he
            lives in the family rather as a relation than
            dependent.                            --Addison.
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   4. Very; in a high degree; that is, in such a degree as can
      not well be expressed; as, he is so good; he planned so
      wisely.
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   5. In the same manner; as has been stated or suggested; in
      this or that condition or state; under these
      circumstances; in this way; -- with reflex reference to
      something just asserted or implied; used also with the
      verb to be, as a predicate.
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            Use him [your tutor] with great respect yourself,
            and cause all your family to do so too. --Locke.
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            It concerns every man, with the greatest
            seriousness, to inquire into those matters, whether
            they be so or not.                    --Tillotson.
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            He is Sir Robert's son, and so art thou. --Shak.
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   6. The case being such; therefore; on this account; for this
      reason; on these terms; -- used both as an adverb and a
      conjuction.
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            God makes him in his own image an intellectual
            creature, and so capable of dominion. --Locke.
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            Here, then, exchange we mutually forgiveness;
            So may the guilt of all my broken vows,
            My perjuries to thee, be all forgotten. --Rowe.
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   7. It is well; let it be as it is, or let it come to pass; --
      used to express assent.
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            And when 't is writ, for my sake read it over,
            And if it please you, so; if not, why, so. --Shak.
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            There is Percy; if your father will do me any honor,
            so; if not, let him kill the next Percy himself.
                                                  --Shak.
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   8. Well; the fact being as stated; -- used as an expletive;
      as, so the work is done, is it?
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   9. Is it thus? do you mean what you say? -- with an upward
      tone; as, do you say he refuses? So? [Colloq.]
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   10. About the number, time, or quantity specified;
       thereabouts; more or less; as, I will spend a week or so
       in the country; I have read only a page or so.
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             A week or so will probably reconcile us. --Gay.
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   Note: See the Note under Ill, adv.
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   So . . . as. So is now commonly used as a demonstrative
      correlative of as when it is the puprpose to emphasize the
      equality or comparison suggested, esp. in negative
      assertions, and questions implying a negative answer. By
      Shakespeare and others so . . . as was much used where as
      . . . as is now common. See the Note under As, 1.
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            So do, as thou hast said.             --Gen. xviii.
                                                  5.
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            As a flower of the field, so he flourisheth. --Ps.
                                                  ciii. 15.
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            Had woman been so strong as men.      --Shak.
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            No country suffered so much as England. --Macaulay.
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   So far, to that point or extent; in that particular. "The
      song was moral, and so far was right." --Cowper.

   So far forth, as far; to such a degree. --Shak. --Bacon.

   So forth, further in the same or similar manner; more of
      the same or a similar kind. See And so forth, under
      And.

   So, so, well, well. "So, so, it works; now, mistress, sit
      you fast." --Dryden. Also, moderately or tolerably well;
      passably; as, he succeeded but so so. "His leg is but so
      so." --Shak.

   So that, to the end that; in order that; with the effect or
      result that.

   So then, thus then it is; therefore; the consequence is.
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The Collaborative International Dictionary of English v.0.48:

So \So\, conj.
   Provided that; on condition that; in case that; if.
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         Though all the winds of doctrine were let loose play
         upon the earth, so truth be in the field, we do
         injuriously, by licensing and prohibiting, to misdoubt
         her strength.                            --Milton.
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The Collaborative International Dictionary of English v.0.48:

So \So\, interj.
   Be as you are; stand still; stop; that will do; right as you
   are; -- a word used esp. to cows; also used by sailors.
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The Collaborative International Dictionary of English v.0.48:

Thionyl \Thi"on*yl\, n. [Thionic + -yl.] (Chem.)
   The hypothetical radical SO, regarded as an essential
   constituent of certain sulphurous compounds; as, thionyl
   chloride.
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WordNet (r) 3.0 (2006):

so
    adv 1: to a very great extent or degree; "the idea is so
           obvious"; "never been so happy"; "I love you so"; "my
           head aches so!"
    2: in a manner that facilitates; "he observed the snakes so he
       could describe their behavior"; "he stooped down so he could
       pick up his hat"
    3: in such a condition or manner, especially as expressed or
       implied; "They're happy and I hope they will remain so"; "so
       live your life that old age will bring no regrets"
    4: to a certain unspecified extent or degree; "I can only go so
       far with this student"; "can do only so much in a day"
    5: in the same way; also; "I was offended and so was he";
       "worked hard and so did she"
    6: in the way indicated; "hold the brush so"; "set up the pieces
       thus"; (`thusly' is a nonstandard variant) [syn: thus,
       thusly, so]
    7: (usually followed by `that') to an extent or degree as
       expressed; "he was so tired he could hardly stand"; "so dirty
       that it smells"
    8: subsequently or soon afterward (often used as sentence
       connectors); "then he left"; "go left first, then right";
       "first came lightning, then thunder"; "we watched the late
       movie and then went to bed"; "and so home and to bed" [syn:
       then, so, and so, and then]
    9: (used to introduce a logical conclusion) from that fact or
       reason or as a result; "therefore X must be true"; "the eggs
       were fresh and hence satisfactory"; "we were young and thence
       optimistic"; "it is late and thus we must go"; "the witness
       is biased and so cannot be trusted" [syn: therefore,
       hence, thence, thus, so]
    10: in truth (often tends to intensify); "they said the car
        would break down and indeed it did"; "it is very cold
        indeed"; "was indeed grateful"; "indeed, the rain may still
        come"; "he did so do it!" [syn: indeed, so]
    n 1: the syllable naming the fifth (dominant) note of any
         musical scale in solmization [syn: sol, soh, so]

Moby Thesaurus II by Grady Ward, 1.0:

118 Moby Thesaurus words for "so":
   a deal, a great deal, a lot, abundantly, accordingly, accurately,
   ad eundem, after this fashion, almighty, along these lines, as,
   as all creation, as all get-out, as long as, as well,
   at what price, awful, awfully, beaucoup, by what mode,
   by what name, ceteris paribus, consequently, considerable,
   considerably, correctly, correspondingly, either, equally,
   equivalently, ergo, evenly, ever so, ever so much, exceedingly,
   exceptionally, extremely, faultlessly, flawlessly, for, galore,
   greatly, hence, highly, how, identically, in consideration of,
   in contemplation of, in great measure, in kind, in like manner,
   in order to, in such wise, in that way, in this way, in what way,
   indifferently, just, just like that, just right, just so, largely,
   like, like so, like that, like this, likewise, mightily, mighty,
   much, muchly, never so, no end, no end of, not a little, only too,
   parlous, perfectly, plenty, powerful, powerfully, precisely,
   pretty, pretty much, properly, proportionately, quite, real,
   really, right, rightly, sic, similarly, so as, so as to,
   so long as, so that, so very much, straight, suchlike, terribly,
   terrifically, then, thereupon, this way, this-a-way, thus,
   thus and so, thus and thus, thusly, thuswise, to, to the skies,
   very, very much, whacking, whopping, without distinction



The Jargon File (version 4.4.7, 29 Dec 2003):

SO
 /S?O/, n.

    1. (also S.O.) Abbrev. for Significant Other, almost invariably written
    abbreviated and pronounced /S?O/ by hackers. Used to refer to one's primary
    relationship, esp. a live-in to whom one is not married. See MOTAS, 
    MOTOS, MOTSS.

    2. [techspeak] The Shift Out control character in ASCII (Control-N,
    0001110).


The Free On-line Dictionary of Computing (30 December 2018):

SO

   1.  Shift Out

   2. Significant Other, almost invariably written abbreviated
   and pronounced /S-O/ by hackers.  Used to refer to one's
   primary relationship, especially a live-in to whom one is not
   married.

   [Jargon File]


The Free On-line Dictionary of Computing (30 December 2018):

so

    The country code for Somalia.

   (1999-01-27)


Easton's 1897 Bible Dictionary:

So
   (Nubian, Sabako), an Ethiopian king who brought Egypt under his
   sway. He was bribed by Hoshea to help him against the Assyrian
   monarch Shalmaneser (2 Kings 17:4). This was a return to the
   policy that had been successful in the reign of Jeroboam I.


Hitchcock's Bible Names Dictionary (late 1800's):

So, a measure for grain; vail