The Collaborative International Dictionary of English v.0.48:

Conserve \Con*serve"\, v. t. [imp. & p. p. Conserved; p. pr. &
   vb. n. Conserving.] [F. conserver, L. conservare; con- +
   servare to keep, guard. See Serve.]
   1. To keep in a safe or sound state; to save; to preserve; to
      protect.
      [1913 Webster]

            The amity which . . . they meant to conserve and
            maintain with the emperor.            --Strype.
      [1913 Webster]

   2. To prepare with sugar, etc., for the purpose of
      preservation, as fruits, etc.; to make a conserve of.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Conserve \Con"serve\, n. [F. conserve, fr. conserver.]
   1. Anything which is conserved; especially, a sweetmeat
      prepared with sugar; a confection.
      [1913 Webster]

            I shall . . . study broths, plasters, and conserves,
            till from a fine lady I become a notable woman.
                                                  --Tatler.
      [1913 Webster]

   2. (Med.) A medicinal confection made of freshly gathered
      vegetable substances mixed with finely powdered refined
      sugar. See Confection.
      [1913 Webster]

   3. A conservatory. [Obs.] --Evelyn.
      [1913 Webster]

WordNet (r) 3.0 (2006):

conserve
    n 1: fruit preserved by cooking with sugar [syn: conserve,
         preserve, conserves, preserves]
    v 1: keep constant through physical or chemical reactions or
         evolutionary change; "Energy is conserved in this process"
    2: keep in safety and protect from harm, decay, loss, or
       destruction; "We preserve these archeological findings"; "The
       old lady could not keep up the building"; "children must be
       taught to conserve our national heritage"; "The museum
       curator conserved the ancient manuscripts" [syn: conserve,
       preserve, maintain, keep up]
    3: use cautiously and frugally; "I try to economize my spare
       time"; "conserve your energy for the ascent to the summit"
       [syn: conserve, husband, economize, economise] [ant:
       blow, squander, waste]
    4: preserve with sugar; "Mom always conserved the strawberries
       we grew in the backyard"

Moby Thesaurus II by Grady Ward, 1.0:

94 Moby Thesaurus words for "conserve":
   Jell-O, attend to, baby-sit, blancmange, candy, care for, chaperon,
   cherish, comfit, compote, confection, confectionery, confiture,
   copyright, foster, frosting, gelatin, glaze, guard, hold back,
   hold on to, honey, husband, icing, jam, jelly, keep, keep alive,
   keep back, keep by one, keep in reserve, keep in store,
   keep intact, keep inviolate, keep on hand, keep safe, keep up,
   keep watch over, lay by, look after, look out for, look to,
   maintain, marmalade, matronize, meringue, mind, minister to,
   mother, mousse, not destroy, not endanger, not expend, not use up,
   not waste, nurse, nurture, patent, preserve, protect, protege,
   provide for, put apart, put aside, put by, register, reserve,
   retain, ride herd on, save, save up, see after, see to, set apart,
   set aside, set by, shepherd, spare, support, sustain, sweet,
   sweet stuff, sweetmeat, sweets, take care of, take charge of, tend,
   tutti-frutti, uphold, watch, watch out for, watch over,
   whipped cream, withhold