The Collaborative International Dictionary of English v.0.48:

Surety \Sure"ty\, n.; pl. Sureties. [OE. seurte, OF.
   se["u]rt['e], F. s[^u]ret['e]. See Sure, Security.]
   1. The state of being sure; certainty; security.
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            Know of a surety, that thy seed shall be a stranger
            in a land that is not theirs.         --Gen. xv. 13.
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            For the more surety they looked round about. --Sir
                                                  P. Sidney.
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   2. That which makes sure; that which confirms; ground of
      confidence or security.
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            [We] our happy state
            Hold, as you yours, while our obedience holds;
            On other surety none.                 --Milton.
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   3. Security against loss or damage; security for payment, or
      for the performance of some act.
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            There remains unpaid
            A hundred thousand more; in surety of the which
            One part of Aquitaine is bound to us. --Shak.
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   4. (Law) One who is bound with and for another who is
      primarily liable, and who is called the principal; one who
      engages to answer for another's appearance in court, or
      for his payment of a debt, or for performance of some act;
      a bondsman; a bail.
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            He that is surety for a stranger shall smart for it.
                                                  --Prov. xi.
                                                  15.
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   5. Hence, a substitute; a hostage. --Cowper.
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   6. Evidence; confirmation; warrant. [Obs.]
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            She called the saints to surety,
            That she would never put it from her finger,
            Unless she gave it to yourself.       --Shak.
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The Collaborative International Dictionary of English v.0.48:

Surety \Sure"ty\, v. t.
   To act as surety for. [Obs.] --Shak.
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WordNet (r) 3.0 (2006):

surety
    n 1: something clearly established
    2: property that your creditor can claim in case you default on
       your obligation; "bankers are reluctant to lend without good
       security" [syn: security, surety]
    3: a prisoner who is held by one party to insure that another
       party will meet specified terms [syn: hostage, surety]
    4: one who provides a warrant or guarantee to another [syn:
       guarantor, surety, warrantor, warranter]
    5: a guarantee that an obligation will be met [syn: security,
       surety]

Moby Thesaurus II by Grady Ward, 1.0:

121 Moby Thesaurus words for "surety":
   absolute certainty, absoluteness, acceptation, acception,
   acquiescence, angel, arrogance, assurance, assuredness, backer,
   bail, bailsman, belief, bond, bondsman, certain knowledge,
   certainness, certainty, certitude, clear sailing, cocksureness,
   confidence, confidentness, conviction, courage, credence, credit,
   credulity, dead certainty, definiteness, dependence, determinacy,
   determinateness, earnest, earnest money, escrow, faith, gage,
   godfather, godparent, guarantee, guarantor, guaranty, handsel,
   harmlessness, hock, hope, hostage, hubris, immunity, indemnity,
   ineluctability, inerrability, inerrancy, inevitability,
   infallibilism, infallibility, insurance, insurer, invulnerability,
   mainpernor, mainprise, mortgagor, necessity, nonambiguity,
   noncontingency, overconfidence, oversureness, overweening,
   overweeningness, patron, pawn, pignus, pledge, poise, pomposity,
   positiveness, predestination, predetermination, pride, probatum,
   protection, proved fact, reception, recognizance, reliance,
   reliance on, replevin, replevy, risklessness, safeguard, safeness,
   safety, security, self-assurance, self-confidence, self-importance,
   self-reliance, settled belief, sponsor, stock, stocks and bonds,
   store, subjective certainty, sureness, suspension of disbelief,
   tie, token payment, trust, truth, unambiguity, undertaking,
   underwriter, unequivocalness, univocity, unmistakableness,
   vadimonium, vadium, warrant, warrantor, warranty



Easton's 1897 Bible Dictionary:

Surety
   one who becomes responsible for another. Christ is the surety of
   the better covenant (Heb. 7:22). In him we have the assurance
   that all its provisions will be fully and faithfully carried
   out. Solomon warns against incautiously becoming security for
   another (Prov. 6:1-5; 11:15; 17:18; 20:16).


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

SURETY, contracts. A person who binds himself for the payment of a sum of
money or for the performance of something else, for another, who is already
bound for the same. A surety differs from a guarantor, and the latter cannot
be sued until after a suit against the principal. 10 Watts, 258.
     2. The surety differs from bail in this, that the latter actually has,
or is by law presumed to have, the custody of his principal, while the
former has no control over him. The bail may surrender his principal in
discharge of his obligation; the surety cannot be discharged by such
surrender.
     3. In Pennsylvania it has been decided that the creditor is bound to
sue the principal when requested by the surety, and the debt is due; and
that when proper notice is given by the surety that unless the principal be
sued, be will consider himself discharged, he will be so considered, unless
the principal be sued. 8 Serg. & Rawle, 116; 15 Serg. & Rawle, 29, 30; S. P.
in Alabama, 9 Porter, R. 409. But in general a creditor may resort to the
surety for the payment of his debt in the first place, without applying to
the principal. 1 Watts, 28O; 7 Ham. part 1, 223. Vide Bouv. Inst. Index,
h.t.; Contribution;  Contracts; Suretyship.