The Collaborative International Dictionary of English v.0.48:

Immovable \Im*mov"a*ble\, a.
   1. Incapable of being moved; firmly fixed; fast; -- used of
      material things; as, an immovable foundation.
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            Immovable, infixed, and frozen round. --Milton.
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   2. Steadfast; fixed; unalterable; unchangeable; -- used of
      the mind or will; as, an immovable purpose, or a man who
      remains immovable.
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   3. Not capable of being affected or moved in feeling or by
      sympathy; unimpressible; impassive. --Dryden.
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   4. (Law.) Not liable to be removed; permanent in place or
      tenure; fixed; as, an immovable estate. See Immovable,
      n. --Blackstone.
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   Immovable apparatus (Med.), an appliance, like the plaster
      of paris bandage, which keeps fractured parts firmly in
      place.

   Immovable feasts (Eccl.), feasts which occur on a certain
      day of the year and do not depend on the date of Easter;
      as, Christmas, the Epiphany, etc.
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The Collaborative International Dictionary of English v.0.48:

Immovable \Im*mov"a*ble\, n.
   1. That which can not be moved.
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   2. pl. (Civil Law) Lands and things adherent thereto by
      nature, as trees; by the hand of man, as buildings and
      their accessories; by their destination, as seeds, plants,
      manure, etc.; or by the objects to which they are applied,
      as servitudes. --Ayliffe. --Bouvier.
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WordNet (r) 3.0 (2006):

immovable
    adj 1: not able or intended to be moved; "the immovable hills"
           [syn: immovable, immoveable, stabile, unmovable]
    n 1: property consisting of houses and land [syn: real
         property, real estate, realty, immovable]