The Collaborative International Dictionary of English v.0.48:

Bailment \Bail"ment\, n.
   1. (Law) The action of bailing a person accused.
      [1913 Webster]

            Bailment . . . is the saving or delivery of a man
            out of prison before he hath satisfied the law.
                                                  --Dalton.
      [1913 Webster]

   2. (Law) A delivery of goods or money by one person to
      another in trust, for some special purpose, upon a
      contract, expressed or implied, that the trust shall be
      faithfully executed. --Blackstone.
      [1913 Webster]

   Note: In a general sense it is sometimes used as
         comprehending all duties in respect to property.
         --Story.
         [1913 Webster]

WordNet (r) 3.0 (2006):

bailment
    n 1: the delivery of personal property in trust by the bailor to
         the bailee

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

BAILMENT, contracts. This word is derived from the French, bailler, to
deliver. 2 Bl. Com. 451; Jones' Bailm. 90 Story on Bailm. c. 1, Sec. 2. It
is a compendious expression, to signify a contract resulting from delivery.
It has been defined to be a delivery of goods on a condition, express or
implied, that they shall be restored by the bailee to the bailor, or
according to his directions, as soon as the purposes for which they are
bailed shall be answered. 1 Jones' Bailm. 1. Or it is a delivery of goods in
trust, on a contract either expressed or implied, that the trust shall be
duly executed, and the goods redelivered, as soon as the time or use for
which they were bailed shall have elapsed or be performed. Jones' Bailm.
117.
     2. Each of these definitions, says Judge Story, seems redundant and
inaccurate if it be the proper office of a definition to include those
things only which belong to the genus or class. Both these definitions
suppose that the goods are to be restored or redelivered; but in a bailment
for sale, as upon a consignment to a factor, no redelivery is contemplated
between the parties. In some cases, no use is contemplated by the bailee, in
others, it is of the essence of the contract: in some cases time is material
to terminAte the contract; in others, time is necessary to give a new
accessorial right. Story,on Bailm. c. 1, Sec. 2.
     3. Mr. Justice Blackstone has defined a bailment to be a delivery of
goods in trust, upon contract, either expressed or implied, that the trust
shall be faithfully executed on the part of the bailee. 2 Bl. Com. 451. And
in another place, as the delivery of goods to another person for a
particular use. 2 Bl. Com. 395. Vide Kent's Comm. Lect. 40, 437.
     4. Mr. Justice Story says, that a bailment is a delivery of a thing in
trust for some special object or purpose, and upon a contract, express or
implied, to conform to the object or purpose of the trust. Story on Bailm.
c. 1, Sec. 2. This corresponds very nearly with the definition of Merlin.
Vide Repertoire, mot Bail.
     5. Bailments are divisible into three kinds: 1. Those in which the
trust is for the benefit of the bailor, as deposits and mandates. 2. Those
in which the trust is for the benefit of the bailee, as gratuitous loans for
use. 3. Those in which the trust is for the benefit of both parties, as
pledges or pawns, and hiring and letting to hire. See Deposit; Hire; Loans;
mandates and Pledges.
     6. Sir William Jones has divided bailments into five sorts, namely: 1.
Depositum, or deposit. 2. Mandatum, or commission without recompense. 3.
Commodatum, or loan for use, without pay. 4. Pignori acceptum, or pawn. 5.
Locatum, or hiring, which is always with reward. This last is subdivided
into, 1. Locatio rei, or hiring, by which the hirer gains a temporary use of
the thing. 2. Locatio operis faciendi, when something is to be done to the
thing delivered. 3. Locatio operis mercium vehendarum, when the thing is
merely to be carried from one place to another. See these several words. As
to the obligations and duties of bailees in general, see Diligence, and
Story on Bailm. c. 1; Chit. on Cont. 141; 3 John. R. 170; 17 Mass. R. 479; 5
Day, 15; 1 Conn. Rep. 487; 10 Johns. R. 1, 471; 12 Johns. R. 144, 232; 11
Johns. R. 107; 15 Johns. R. 39; 2 John. C. R. 100; 2 Caines' Cas. 189; 19
Johns. R. 44; 14 John. R. 175; 2 Halst. 108; 2 South. 738; 2 Harr. & M'Hen.
453; 1 Rand. 3; 2 Hawks, 145; 1 Murphy, 417; 1 Hayw. 14; 1 Rep. Con. Ct.
121, 186; 2 Rep. Con. Ct. 239; 1 Bay, 101; 2 Nott & M'Cord, 88, 489; 1
Browne, 43, 176; 2 Binn. 72; 4 Binn. 127; 5 Binn. 457; 6 Binn. 129; 6 Serg.
& Rawle, 439; 8 Serg. & Rawle, 500, 533; 14 Serg. & R. 275; Bac. Ab. h. t.;
1 Bouv. Inst. n. 978-1099.