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

1. \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.
            Know of a surety, that thy seed shall be a stranger
            in a land that is not theirs.         --Gen. xv. 13.
            For the more surety they looked round about. --Sir
                                                  P. Sidney.
   2. That which makes sure; that which confirms; ground of
      confidence or security.
            [We] our happy state Hold, as you yours, while our
            obedience holds; On other surety none. --Milton.
   3. Security against loss or damage; security for payment, or
      for the performance of some act.
            There remains unpaid A hundred thousand more; in
            surety of the which One part of Aquitaine is bound
            to us.                                --Shak.
   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.
            He that is surety for a stranger shall smart for it.
                                                  --Prov. xi.
                                                  15.
   5. Hence, a substitute; a hostage. --Cowper.
   6. Evidence; confirmation; warrant. [Obs.]
            She called the saints to surety, That she would
            never put it from her finger, Unless she gave it to
            yourself.                             --Shak.
   

2. \Sure"ty\, v. t.
   To act as surety for. [Obs.] --Shak.
   

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).