The Collaborative International Dictionary of English v.0.48:

Corporation \Cor`po*ra"tion\ (k[^o]r`p[-o]*r[=a]"sh[u^]n), n.
   [L. corporatio incarnation: cf. F. corporation corporation.]
   A body politic or corporate, formed and authorized by law to
   act as a single person, and endowed by law with the capacity
   of succession; a society having the capacity of transacting
   business as an individual.
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   Note: Corporations are aggregate or sole. Corporations
         aggregate consist of two or more persons united in a
         society, which is preserved by a succession of members,
         either forever or till the corporation is dissolved by
         the power that formed it, by the death of all its
         members, by surrender of its charter or franchises, or
         by forfeiture. Such corporations are the mayor and
         aldermen of cities, the head and fellows of a college,
         the dean and chapter of a cathedral church, the
         stockholders of a bank or insurance company, etc. A
         corporation sole consists of a single person, who is
         made a body corporate and politic, in order to give him
         some legal capacities, and especially that of
         succession, which as a natural person he can not have.
         Kings, bishops, deans, parsons, and vicars, are in
         England sole corporations. A fee will not pass to a
         corporation sole without the word "successors" in the
         grant. There are instances in the United States of a
         minister of a parish seized of parsonage lands in the
         right of his parish, being a corporation sole, as in
         Massachusetts. Corporations are sometimes classified as
         public and private; public being convertible with
         municipal, and private corporations being all
         corporations not municipal.
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   Close corporation. See under Close.
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The Collaborative International Dictionary of English v.0.48:

Close \Close\ (kl[=o]s), a. [Compar. Closer (kl[=o]"s[~e]r);
   superl. Closest.] [Of. & F. clos, p. p. of clore. See
   Close, v. t.]
   1. Shut fast; closed; tight; as, a close box.
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            From a close bower this dainty music flowed.
                                                  --Dryden.
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   2. Narrow; confined; as, a close alley; close quarters. "A
      close prison." --Dickens.
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   3. Oppressive; without motion or ventilation; causing a
      feeling of lassitude; -- said of the air, weather, etc.
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            If the rooms be low-roofed, or full of windows and
            doors, the one maketh the air close, . . . and the
            other maketh it exceeding unequal.    --Bacon.
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   4. Strictly confined; carefully quarded; as, a close
      prisoner.
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   5. Out of the way observation; secluded; secret; hidden. "He
      yet kept himself close because of Saul." --1 Chron. xii. 1
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            "Her close intent."                   --Spenser.
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   6. Disposed to keep secrets; secretive; reticent. "For
      secrecy, no lady closer." --Shak.
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   7. Having the parts near each other; dense; solid; compact;
      as applied to bodies; viscous; tenacious; not volatile, as
      applied to liquids.
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            The golden globe being put into a press, . . . the
            water made itself way through the pores of that very
            close metal.                          --Locke.
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   8. Concise; to the point; as, close reasoning. "Where the
      original is close no version can reach it in the same
      compass." --Dryden.
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   9. Adjoining; near; either in space; time, or thought; --
      often followed by to.
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            Plant the spring crocuses close to a wall.
                                                  --Mortimer.
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            The thought of the Man of sorrows seemed a very
            close thing -- not a faint hearsay.   --G. Eliot.
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   10. Short; as, to cut grass or hair close.
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   11. Intimate; familiar; confidential.
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             League with you I seek
             And mutual amity, so strait, so close,
             That I with you must dwell, or you with me.
                                                  --Milton.
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   12. Nearly equal; almost evenly balanced; as, a close vote.
       "A close contest." --Prescott.
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   13. Difficult to obtain; as, money is close. --Bartlett.
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   14. Parsimonious; stingy. "A crusty old fellow, as close as a
       vise." --Hawthorne.
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   15. Adhering strictly to a standard or original; exact;
       strict; as, a close translation. --Locke.
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   16. Accurate; careful; precise; also, attentive; undeviating;
       strict; not wandering; as, a close observer.
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   17. (Phon.) Uttered with a relatively contracted opening of
       the mouth, as certain sounds of e and o in French,
       Italian, and German; -- opposed to open.
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   Close borough. See under Borough.

   Close breeding. See under Breeding.

   Close communion, communion in the Lord's supper, restricted
      to those who have received baptism by immersion.

   Close corporation, a body or corporation which fills its
      own vacancies.

   Close fertilization. (Bot.) See Fertilization.

   Close harmony (Mus.), compact harmony, in which the tones
      composing each chord are not widely distributed over
      several octaves.

   Close time, a fixed period during which killing game or
      catching certain fish is prohibited by law.

   Close vowel (Pron.), a vowel which is pronounced with a
      diminished aperture of the lips, or with contraction of
      the cavity of the mouth.

   Close to the wind (Naut.), directed as nearly to the point
      from which the wind blows as it is possible to sail;
      closehauled; -- said of a vessel.
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WordNet (r) 3.0 (2006):

close corporation
    n 1: a corporation owned by a few people; shares have no public
         market [syn: closed corporation, close corporation,
         private corporation, privately held corporation]