The Collaborative International Dictionary of English v.0.48:

Sovereign \Sov"er*eign\ (? or ?; 277), n.
   1. The person, body, or state in which independent and
      supreme authority is vested; especially, in a monarchy, a
      king, queen, or emperor.
      [1913 Webster]

            No question is to be made but that the bed of the
            Mississippi belongs to the sovereign, that is, to
            the nation.                           --Jefferson.
      [1913 Webster]

   2. A gold coin of Great Britain, on which an effigy of the
      head of the reigning king or queen is stamped, valued at
      one pound sterling, or about $4.86.
      [1913 Webster]

   3. (Zool.) Any butterfly of the tribe Nymphalidi, or genus
      Basilarchia, as the ursula and the viceroy.
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   Syn: King; prince; monarch; potentate; emperor.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sovereign \Sov"er*eign\ (? or ?; 277), a. [OE. soverain,
   sovereyn, OF. soverain, suvrain, F. souverain, LL. superanus,
   fr. L. superus that is above, upper, higher, fr. super above.
   See Over, Super, and cf. Soprano. The modern spelling
   is due to a supposed connection with reign.]
   1. Supreme or highest in power; superior to all others;
      chief; as, our sovereign prince.
      [1913 Webster]

   2. Independent of, and unlimited by, any other; possessing,
      or entitled to, original authority or jurisdiction; as, a
      sovereign state; a sovereign discretion.
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   3. Princely; royal. "Most sovereign name." --Shak.
      [1913 Webster]

            At Babylon was his sovereign see.     --Chaucer.
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   4. Predominant; greatest; utmost; paramount.
      [1913 Webster]

            We acknowledge him [God] our sovereign good.
                                                  --Hooker.
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   5. Efficacious in the highest degree; effectual; controlling;
      as, a sovereign remedy. --Dryden.
      [1913 Webster]

            Such a sovereign influence has this passion upon the
            regulation of the lives and actions of men. --South.
      [1913 Webster]

   Sovereign state, a state which administers its own
      government, and is not dependent upon, or subject to,
      another power.
      [1913 Webster]

WordNet (r) 3.0 (2006):

sovereign
    adj 1: (of political bodies) not controlled by outside forces;
           "an autonomous judiciary"; "a sovereign state" [syn:
           autonomous, independent, self-governing,
           sovereign]
    2: greatest in status or authority or power; "a supreme
       tribunal" [syn: sovereign, supreme]
    n 1: a nation's ruler or head of state usually by hereditary
         right [syn: sovereign, crowned head, monarch]

Moby Thesaurus II by Grady Ward, 1.0:

201 Moby Thesaurus words for "sovereign":
   absolute, all-knowing, all-powerful, all-seeing, all-wise,
   almighty, anointed king, arch, ascendant, at the head, autarchic,
   autarkic, autonomous, banner, blue-ribbon, boss, boundless,
   capital, cardinal, central, champion, changeless, chief, chieftain,
   classical, coin, commanding, controlling, creating, creative,
   crown, crowned head, crowning, directing, dominant, double eagle,
   doubloon, ducat, dynast, dynastic, eagle, emperor, eternal,
   eternally the same, everlasting, fine, first, first-class,
   five-dollar gold piece, focal, foremost, free-spirited,
   freewheeling, general, glorious, gold piece, good, governing,
   grand duke, great, guiding, guinea, half crown, half eagle,
   hallowed, hard money, head, headmost, hegemonic, hegemonistic,
   high chief, highest, holy, immortal, immutable, imperator,
   imperatorial, imperatorious, imperial, imperious, in ascendancy,
   in charge, in chief, in the ascendant, independent,
   individualistic, infinite, inner-directed, just, king,
   king-emperor, kinglet, kinglike, kingly, leading, limitless,
   lord paramount, loving, luminous, magisterial, main, majestic,
   majesty, making, master, merciful, moidore, monarch, monarchal,
   monarchial, monarchic, monarchical, napoleon, neutral, nonaligned,
   nonpartisan, number one, numinous, omnipotent, omnipresent,
   omniscient, one, overbearing, overlord, overruling, paramount,
   permanent, perpetual, petty king, piece, piece of money,
   piece of silver, plenipotentiary, potentate, pound sovereign,
   predominant, predominate, preeminent, prepollent, preponderant,
   preponderate, prepotent, prevailing, prevalent, primal, primary,
   prime, prince, prince consort, princelike, princely, principal,
   purple, queenlike, queenly, radiant, ranking, regal, regnant,
   regulating, regulative, regulatory, reigning, roll of coins,
   rouleau, royal, royal personage, royalty, ruler, ruling, sacred,
   self-contained, self-dependent, self-determined, self-directing,
   self-governed, self-governing, self-reliant, self-subsistent,
   self-sufficient, self-supporting, separate, shaping, specie, star,
   stellar, supereminent, supreme, suzerain, ten-dollar gold piece,
   tetrarch, third-force, third-world, timeless, topflight,
   twenty-dollar gold piece, ubiquitous, unbounded, unchanging,
   undefined, unlimited



Bouvier's Law Dictionary, Revised 6th Ed (1856):

SOVEREIGN, Eng. law. The name of a gold coin of Great Britain of the value
of one pound sterling.



Bouvier's Law Dictionary, Revised 6th Ed (1856):

SOVEREIGN. A chief ruler with supreme power; one possessing sovereignty.
(q.v.) It is also applied to a king or other magistrate with limited powers.
     2. In the United States the sovereignty resides in the body of the
people. Vide Rutherf. Inst. 282.