Source : Webster's Revised Unabridged Dictionary (1913)

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.

   2. Relating to religion, or to the services of religion; not
      secular; religious; as, sacred history.

            Smit with the love of sacred song.    --Milton.

   3. Designated or exalted by a divine sanction; possessing the
      highest title to obedience, honor, reverence, or
      veneration; entitled to extreme reverence; venerable.

            Such neighbor nearness to our sacred [royal] blood
            Should nothing privilege him.         --Shak.

            Poet and saint to thee alone were given, The two
            most sacred names of earth and heaven. --Cowley.

   4. Hence, not to be profaned or violated; inviolable.

            Secrets of marriage still are sacred held. --Dryden.

   5. Consecrated; dedicated; devoted; -- with to.

            A temple, sacred to the queen of love. --Dryden.

   6. Solemnly devoted, in a bad sense, as to evil, vengeance,
      curse, or the like; accursed; baleful. [Archaic]

            But, to destruction sacred and devote. --Milton.

Source : WordNet®

sacred
     adj 1: concerned with religion or religious purposes; "sacred
            texts"; "sacred rites"; "sacred music" [ant: {profane}]
     2: worthy of respect or dedication; "saw motherhood as woman's
        sacred calling"
     3: made or declared or believed to be holy; devoted to a deity
        or some religious ceremony or use; "a consecrated chursh";
        "the sacred mosque"; "sacred elephants"; "sacred bread and
        wine"; "sanctified wine" [syn: {consecrated}, {sanctified}]
     4: worthy of religious veneration; "the sacred name of Jesus";
        "Jerusalem's hallowed soil" [syn: {hallowed}]
     5: (often followed by `to') devoted exclusively to a single use
        or purpose or person; "a fund sacred to charity"; "a
        morning hour sacred to study"; "a private office sacred to
        the President"

Source : Free On-Line Dictionary of Computing

sacred
     
         Reserved for exclusive use by something.  The term
        might mean only writable by whatever it is sacred to.
     
        For example, "Register 7 is sacred to the interrupt handler"
        would mean that if any other code changed the contents of
        register 7, dire consequences would ensue.
     
        [{Jargon File}]
     
        (2002-12-30)