The Collaborative International Dictionary of English v.0.48:

Sacred \Sa"cred\, a. [Originally p. p. of OE. sacren to
   consecrate, F. sacrer, fr. L. sacrare, fr. sacer sacred,
   holy, cursed. Cf. Consecrate, Execrate, Saint,
   Sexton.]
   1. Set apart by solemn religious ceremony; especially, in a
      good sense, made holy; set apart to religious use;
      consecrated; not profane or common; as, a sacred place; a
      sacred day; sacred service.
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   2. Relating to religion, or to the services of religion; not
      secular; religious; as, sacred history.
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            Smit with the love of sacred song.    --Milton.
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   3. Designated or exalted by a divine sanction; possessing the
      highest title to obedience, honor, reverence, or
      veneration; entitled to extreme reverence; venerable.
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            Such neighbor nearness to our sacred [royal] blood
            Should nothing privilege him.         --Shak.
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            Poet and saint to thee alone were given,
            The two most sacred names of earth and heaven.
                                                  --Cowley.
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   4. Hence, not to be profaned or violated; inviolable.
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            Secrets of marriage still are sacred held. --Dryden.
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   5. Consecrated; dedicated; devoted; -- with to.
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            A temple, sacred to the queen of love. --Dryden.
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   6. Solemnly devoted, in a bad sense, as to evil, vengeance,
      curse, or the like; accursed; baleful. [Archaic]
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            But, to destruction sacred and devote. --Milton.
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   Society of the Sacred Heart (R.C. Ch.), a religious order
      of women, founded in France in 1800, and approved in 1826.
      It was introduced into America in 1817. The members of the
      order devote themselves to the higher branches of female
      education.

   Sacred baboon. (Zool.) See Hamadryas.

   Sacred bean (Bot.), a seed of the Oriental lotus (Nelumbo
      speciosa or Nelumbium speciosum), a plant resembling a
      water lily; also, the plant itself. See Lotus.

   Sacred beetle (Zool.) See Scarab.

   Sacred canon. See Canon, n., 3.

   Sacred fish (Zool.), any one of numerous species of
      fresh-water African fishes of the family Mormyridae.
      Several large species inhabit the Nile and were considered
      sacred by the ancient Egyptians; especially Mormyrus
      oxyrhynchus.

   Sacred ibis. See Ibis.

   Sacred monkey. (Zool.)
      (a) Any Asiatic monkey of the genus Semnopithecus,
          regarded as sacred by the Hindoos; especially, the
          entellus. See Entellus.
      (b) The sacred baboon. See Hamadryas.
      (c) The bhunder, or rhesus monkey.

   Sacred place (Civil Law), the place where a deceased person
      is buried.
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   Syn: Holy; divine; hallowed; consecrated; dedicated; devoted;
        religious; venerable; reverend.
        [1913 Webster] -- Sa"cred*ly, adv. -- Sa"cred*ness,
        n.
        [1913 Webster] Sacrific

WordNet (r) 3.0 (2006):

sacredness
    n 1: the quality of being sacred