The Collaborative International Dictionary of English v.0.48:

Prison \Pris"on\ (?; 277), n. [F., fr. L. prehensio, prensio, a
   seizing, arresting, fr. prehendre, prendere, to lay hold of,
   to seize. See Prehensile, and cf. Prize, n.,
   Misprision.]
   1. A place where persons are confined, or restrained of
      personal liberty; hence, a place or state o? confinement,
      restraint, or safe custody.
      [1913 Webster]

            Bring my soul out of prison, that I may praise thy
            name.                                 --Ps. cxlii.
                                                  7.
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            The tyrant Aeolus, . . .
            With power imperial, curbs the struggling winds,
            And sounding tempests in dark prisons binds.
                                                  --Dryden.
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   2. Specifically, a building for the safe custody or
      confinement of criminals and others committed by lawful
      authority.
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   Prison bars, or Prison base. See Base, n., 24.

   Prison breach. (Law) See Note under 3d Escape, n., 4.

   Prison house, a prison. --Shak.

   Prison ship (Naut.), a ship fitted up for the confinement
      of prisoners.

   Prison van, a carriage in which prisoners are conveyed to
      and from prison.
      [1913 Webster]

WordNet (r) 3.0 (2006):

prison house
    n 1: a prisonlike situation; a place of seeming confinement
         [syn: prison, prison house]
    2: a correctional institution where persons are confined while
       on trial or for punishment [syn: prison, prison house]