The Collaborative International Dictionary of English v.0.48:

homework \homework\ n.
   1. preparatory school work done outside school (especially at
      home).

   Syn: prep, preparation.
        [WordNet 1.5]

   2. Hence: [fig.] Studies or other preparatory work done prior
      to some activity; -- usually used of preparations for
      activities of significance or consequence for the
      performer; as, the candidate didn't do her homework well
      and was outclassed in the debate.
      [PJC]

   3. Paid work done at home, especially piecework.
      [PJC]

WordNet (r) 3.0 (2006):

homework
    n 1: preparatory school work done outside school (especially at
         home) [syn: homework, prep, preparation]