From 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]
From 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]