The Collaborative International Dictionary of English v.0.48:

Warranty \War"rant*y\, n.; pl. Warranties. [OF. warantie, F.
   garantie. See Warrant, n., and cf. Guaranty.]
   [1913 Webster]
   1. (Anc. Law) A covenant real, whereby the grantor of an
      estate of freehold and his heirs were bound to warrant and
      defend the title, and, in case of eviction by title
      paramount, to yield other lands of equal value in
      recompense. This warranty has long singe become obsolete,
      and its place supplied by personal covenants for title.
      Among these is the covenant of warranty, which runs with
      the land, and is in the nature of a real covenant. --Kent.
      [1913 Webster]

   2. (Modern Law) An engagement or undertaking, express or
      implied, that a certain fact regarding the subject of a
      contract is, or shall be, as it is expressly or impliedly
      declared or promised to be. In sales of goods by persons
      in possession, there is an implied warranty of title, but,
      as to the quality of goods, the rule of every sale is,
      Caveat emptor. --Chitty. Bouvier.
      [1913 Webster]

   3. (Insurance Law) A stipulation or engagement by a party
      insured, that certain things, relating to the subject of
      insurance, or affecting the risk, exist, or shall exist,
      or have been done, or shall be done. These warranties,
      when express, should appear in the policy; but there are
      certain implied warranties. --Bouvier.
      [1913 Webster]

   4. Justificatory mandate or precept; authority; warrant. [R.]
      --Shak.
      [1913 Webster]

            If they disobey precept, that is no excuse to us,
            nor gives us any warranty . . . to disobey likewise.
                                                  --Kettlewe??.
      [1913 Webster]

   5. Security; warrant; guaranty.
      [1913 Webster]

            The stamp was a warranty of the public. --Locke.
      [1913 Webster]

   Syn: See Guarantee.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Warranty \War"rant*y\, v. t.
   To warrant; to guarantee.
   [1913 Webster]

WordNet (r) 3.0 (2006):

warranty
    n 1: a written assurance that some product or service will be
         provided or will meet certain specifications [syn:
         guarantee, warrant, warrantee, warranty]

Moby Thesaurus II by Grady Ward, 1.0:

57 Moby Thesaurus words for "warranty":
   affidavit, assurance, attestation, authority, authorization,
   avouch, avouchment, bail, bill of health, bond, certificate,
   certificate of proficiency, certification, clearance, countenance,
   credential, deposition, diploma, empowerment, enabling,
   enfranchisement, entitlement, faith, fiat, guarantee, guaranty,
   indemnity, insurance, navicert, notarized statement, note, oath,
   parole, pledge, plight, promise, ratification, sanction, security,
   sheepskin, solemn declaration, stocks and bonds, surety,
   sworn statement, testamur, testimonial, ticket, tie, troth, visa,
   vise, voucher, vow, warrant, witness, word, word of honor



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

WARRANTY, contracts. This word has several significations, as it is applied
to the conveyance and sale of lands, to the sale of goods, and to the
contract of insurance.
     2.-1. The ancient law relating to warranties of land was full of
subtleties and intricacies; it occupied the attention of the most eminent
writers on the English law, and it was declared by Lord Coke, that the
learning of warranties was one of the most curious and cunning learnings of
the law; but it is now of little use even in England. The warranty was a
covenant real, whereby the grantor of an estate of freehold, and his heirs,
were bound to warrant the title; and either upon voucher, or judgment in, a
writ of warrantia chartae, to yield other lands to the value of those from
which there had been an eviction by paramount title Co. Litt. 365; Touchst.;
181 Bac. Ab. h.t.; the heir of the warrantor was bound only on condition
that he had, as assets, other lands of equal value by descent.
     3. Warranties were lineal and collateral.
     4. Lineal, when the heir derived title to the land warranted, either
from or through the ancestor who made the warranty.
     5. Collateral warranty was when the heir's title was not derived from
the warranting ancestor, and yet it barred the heir from claiming the land
by any collateral title, upon the presumption that he might thereafter have
assets by descent from or through the ancestor; and it imposed upon him the
obligation of giving the warrantee other lands, in case of eviction,
provided he had assets. 2 Bl. Com. 301, 302.
     6. The statute of 4 Anne, c. 16, annulled these collateral warrantees,
which bid become a great grievance. Warranty in its original form, it is
presumed, has never been known in the United States. The more plain and
pliable form of a covenant has been adopted in its place and this covenant,
like all other covenants, has always been held to sound in damages which
after judgment may be recovered out of the personal or real estate, as in
other cases. Vide 4 Kent, Com. 457; 3 Rawle's R. 67, n.; 2 Wheat. R. 45; 9
Serg. & Rawle, 268; 11 Serg. & Rawle, 109; 4 Dall. Rep. 442; 2 Saund. 38, n.
5.
     7.-2. Warranties in relation, to the sale of personal chattels are of
two kinds, express or implied.
     8. An express warranty is one by which the warrantor covenants or
undertakes to insure that the thing which is the subject of the. contract,
is or is not as there mentioned; as, that a horse is sound; that he is not
five years old.
     9. An implied warranty is one which, not being expressly made, the law
implies by the fact of the sale; for example, the seller is, understood to
warrant the title of goods be sells, when they are in his possession at the
time of the sale; Ld. Raym. 593; 1 Salk.. 210; but if they are not then in
his possession, the rule of caveat emptor applies, and the buyer purchases
at his risk. Cro. Jac. 197.
     10. In general there is no implied warranty of the quality of the goods
sold. 2 Kent, Com. 374; Co. Litt. 102, a; 2 Black Comm. 452; Bac. Abr.
Action on the case E; 2 Com. Contr. 263; Dougl. 20; 2 East, 31 4; Id. 448,
n.; Ross on Vend. c. 6; 1 Johns. R. 274; 4 Conn. R. 428; 1 Dall. Rep. 91; 10
Mass. R. 197; 20 Johns. Rep., 196; 3 Yeates, R. 262; 1 Pet. Rep. 317; 12
Serg. & Rawle, 181; 1 Hard. Kent. Rep. 531; 1 Murphy, Rep. 138; 2 Id. 245; 4
Haywood's Term. R. 227; 2 Caines' Rep. 48. The rule of the civil law was,
that a fair price implied a warranty of title; Dig. 21, 2, 1; this rule, has
been adopted in Louisiana; Code, art. 247 7; and in South Carolina. 1 Bay,
R. 324; 2 Bay, R. 380 1 Const. R. 182; 2 Const. R. 353. Vide Harr. Dig.
Sale, II. 8; 12 East, R. 452.
     11.-3. In the contract of insurance, there are certain warranties which
are inducements to the insurer to enter into it. A warranty of this kind is
a stipulation or agreement on the part of the insured, in the nature of a
condition precedent. It may be affirmative; as where the insured undertakes
for the truth of some positive allegation: as, that the thing insured is
neutral property: or, it may be promissory; as, that the ship shall sail on
or before a given day. 6 N. S. 53.
     12. Warranties are also express or implied. An express warranty is a
particular stipulation introduced into the written contract, by the
agreement of the parties; an implied warranty is an agreement which
necessarily results from the nature of the contract: as, that the ship shall
be seaworthy when she sails on the voyage insured.
     13. The warranty being in the nature of a condition precedent, it is to
be performed by the insured, before he can demand the performance of the
contract on the part of the insurer. Marsh. Inst. B. 1, c. 9. See,
generally, Bouv. Inst. Index, h.t.



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

WARRANTY, VOUCHER TO, practice. A warranty is a contract real, annexed to
lands and tenements, whereby a man is bound to defend such lands and
tenements from another person; and in case of eviction by title paramount,
to give him lands of equal value.
     2. Voucher to warranty is the calling of such warrantor into court by
the party warranted, (when tenant in a real action brought for recovery of
such lands,) to defend the suit for him; Co. Litt. 101, b; Com. Dig.
Voucher, A 1; Booth, 43 2 Saund. 32, n. 1; and the time of such voucher is
after the demandant has counted. It lies in most real and mixed actions, but
not in personal. Where the voucher has been made and allowed by the court,
the vouchee either voluntarily appears, or there issues a judicial writ
(called a summons ad warrantizandum,) commanding the sheriff to summon him.
Where he, either voluntarily or in obedience to this writ, appears and
offers to warrant the land to the tenant, it is called entering into the
warranty; after which he is considered as tenant in the action, in the place
of the original tenant. The demandant then counts against him de novo, the
vouchee pleads to the new count, and the cause proceeds to issue. 2 Inst.
241 a; 2 Saund. 32, n. 1; Booth, 46.
     3. Voucher of warranty is, in the present rarity of real actions,
unknown in practice. Steph. Plead. 85.