The Collaborative International Dictionary of English v.0.48:

Limbo \Lim"bo\ (l[i^]m"b[-o]), n. [Jamaican E. limba to bend,
   fr. E. limber (1950) --MW10]
   A West Indian dance contest, in which participants must dance
   under a pole which is lowered successively until only one
   participant can successfully pass under, without falling. It
   is often performed at celebrations, such as weddings.
   [PJC]

The Collaborative International Dictionary of English v.0.48:

Limbo \Lim"bo\ (l[i^]m"b[-o]), Limbus \Lim"bus\ (l[i^]m"b[u^]s),
   n. [L. limbus border, edge in limbo on the border. Cf. Limb
   border.]
   1. (Scholastic Theol.) An spiritual region where certain
      classes of souls were supposed to await the last judgment.
      [1913 Webster]

            As far from help as Limbo is from bliss. --Shak.
      [1913 Webster]

            A Limbo large and broad, since called
            The Paradise of fools.                --Milton.
      [1913 Webster]

   Note: The limbus patrum was considered as a place for the
         souls of good men who lived before the coming of our
         Savior. The limbus infantium was said to be a similar
         place for the souls of unbaptized infants. To these was
         added, in the popular belief, the limbus fatuorum, or
         fool's paradise, regarded as a receptacle of all vanity
         and nonsense.
         [1913 Webster]

   2. Hence: Any real or imaginary place of restraint or
      confinement; a prison; as, to put a man in limbo.
      [1913 Webster]

   3. Hence: A state of waiting, or uncertainty, in which final
      judgment concerning the outcome of a decision is
      postponed, perhaps indefinitely; neglect for an indefinite
      time; as, the proposal was left in limbo while opponents
      and proponents refused to compromise.
      [PJC]

   4. (Anat.) A border or margin; as, the limbus of the cornea.
      [1913 Webster]

WordNet (r) 3.0 (2006):

limbo
    n 1: the state of being disregarded or forgotten [syn:
         oblivion, limbo]
    2: an imaginary place for lost or neglected things
    3: (theology) in Roman Catholicism, the place of unbaptized but
       innocent or righteous souls (such as infants and virtuous
       individuals)

Moby Thesaurus II by Grady Ward, 1.0:

35 Moby Thesaurus words for "limbo":
   Abaddon, Gehenna, Hades, Naraka, Pandemonium, Sheol, Tophet,
   avichi, cage, coop, enclosure, hell, in abeyance, infernal regions,
   inferno, jahannan, lower world, nether world, on the shelf, pen,
   penfold, perdition, pinfold, place of confinement,
   place of torment, pound, purgatory, shades below, suspended,
   the abyss, the bottomless pit, the grave, the pit, treading water,
   underworld