The Collaborative International Dictionary of English v.0.48:

Curator \Cu*ra"tor\ (k?-r?"t?r). n. [L., fr. curare to take care
   of, fr. cura care.]
   1. One who has the care and superintendence of anything, as
      of a museum; a custodian; a keeper.
      [1913 Webster]

   2. One appointed to act as guardian of the estate of a person
      not legally competent to manage it, or of an absentee; a
      trustee; a guardian.
      [1913 Webster]

WordNet (r) 3.0 (2006):

curator
    n 1: the custodian of a collection (as a museum or library)
         [syn: curator, conservator]

Moby Thesaurus II by Grady Ward, 1.0:

105 Moby Thesaurus words for "curator":
   MC, accountant, air warden, attendant, attorney, auditor, bailiff,
   bibliognost, bibliographer, biblioklept, bibliolater, bibliomane,
   bibliomaniac, bibliopegist, bibliophage, bibliophile, bibliopole,
   bibliopolist, bibliotaph, bibliothec, bibliothecaire,
   bibliothecary, book agent, book collector, book printer,
   book publisher, book salesman, book-stealer, bookbinder,
   bookdealer, bookkeeper, booklover, bookmaker, bookman, bookseller,
   bookworm, bursar, butler, caretaker, cashier, cashkeeper,
   castellan, cataloger, chamberlain, chief librarian, college editor,
   comptroller, conservator, controller, copy editor, croupier,
   custodian, depositary, depository, dictionary editor, editor,
   editor-in-chief, emcee, executive editor, factor,
   financial officer, forest ranger, game warden, gamekeeper,
   governor, guardian, guardian angel, housekeeper, janitor,
   juvenile editor, keeper, landreeve, librarian, library director,
   lifeguard, lifesaver, liquidator, majordomo, managing editor,
   master of ceremonies, next friend, paymaster, permissions editor,
   philobiblist, printer, prochein ami, proctor, procurator,
   production editor, publisher, purse bearer, purser, ranger,
   receiver, reference editor, reference librarian, seneschal,
   shepherd, steward, textbook editor, trade editor, treasurer,
   trustee, warden, warder



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

CURATOR, persons, contracts. One who has been legally appointed to take care
of the interests of one who, on account of his youth, or defect of his
understanding, or for some other cause, is unable to attend to them himself.
     2. There are curators ad bona, of property, who administer the estate
of a minor, take care of his person, and intervene in all his contracts;
curators ad litem, of suits, who assist the minor in courts of justice, and
act as curator ad bona in cases where the interests of the curator are
opposed to the interests of the minor. Civ. Code of Louis. art. 357 to 366.
There are also curators of insane persons Id. art. 31; and of vacant
successions and absent heirs. Id. art. 1105 to 1125.
     3. The term curator is usually employed in the civil law, for that of
guardian.