The Collaborative International Dictionary of English v.0.48:

offal \of"fal\, n. [Off + fall.]
   1. The rejected or waste parts of any process, especially the
      inedible parts of a butchered animal, such as the viscera.
      [1913 Webster +PJC]

   2. A dead body; carrion. --Shak.
      [1913 Webster]

   3. That which is thrown away as worthless or unfit for use;
      refuse; rubbish.
      [1913 Webster]

            The offals of other professions.      --South.
      [1913 Webster]

WordNet (r) 3.0 (2006):

offal
    n 1: viscera and trimmings of a butchered animal often
         considered inedible by humans