The Collaborative International Dictionary of English v.0.48:

Hausen \Hau"sen\ (h[add]"s[e^]n), n. [G.] (Zool.)
   A large sturgeon (Acipenser huso syn. Huso huso) from the
   region of the Black Sea; also called Beluga. It is
   sometimes twelve feet long, and provides the highest quality
   caviar.
   [1913 Webster +PJC]

The Collaborative International Dictionary of English v.0.48:

Huso \Hu"so\, n. [NL., fr. G. hausen, and E. isinglass.] (Zool.)
      (a) A large European sturgeon (Huso huso or Acipenser
          huso), inhabiting the region of the Black and Caspian
          Seas. It sometimes attains a length of more than
          twelve feet, and a weight of two thousand pounds.
          Called also hausen and beluga. It is the source of
          the finest and most esteemed caviar.
      (b) The huchen, a large salmon.
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Isinglass \I"sin*glass\, n. [Prob. corrupted fr. D. huizenblas
   (akin to G. hausenblase), lit., bladder of the huso, or large
   sturgeon; huizen sturgeon + blas bladder. Cf. Bladder,
   Blast a gust of wind.]
   [1913 Webster]
   1. A semitransparent, whitish, and very pure form of gelatin,
      chiefly prepared from the sounds or air bladders of
      various species of sturgeons (as the Acipenser huso)
      found in the rivers of Western Russia. It used for making
      jellies, as a clarifier, etc. Cheaper forms of gelatin are
      not unfrequently so called. Called also fish glue.
      [1913 Webster]

   2. (Min.) A popular name for mica, especially when in thin
      sheets.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Acipenser huso
    n 1: valuable source of caviar and isinglass; found in Black and
         Caspian seas [syn: beluga, hausen, white sturgeon,
         Acipenser huso]