The Collaborative International Dictionary of English v.0.48:

Alienage \Al"ien*age\, n. [Cf. OF. ali['e]nage.]
   1. The state or legal condition of being an alien.
      [1913 Webster]

   Note: The disabilities of alienage are removable by
         naturalization or by special license from the State of
         residence, and in some of the United States by
         declaration of intention of naturalization. --Kent.
         Wharton.
         [1913 Webster]

               Estates forfeitable on account of alienage.
                                                  --Story.
         [1913 Webster]

   2. The state of being alienated or transferred to another.
      --Brougham.
      [1913 Webster]

WordNet (r) 3.0 (2006):

alienage
    n 1: the quality of being alien [syn: alienage, alienism]