The Collaborative International Dictionary of English v.0.48:

bioengineering \bi`o*en*gin*eer"ing\ n.
   1. biological science applied to the study the relation
      between workers and their environments.

   Syn: ergonomics.
        [WordNet 1.5]

   2. the application of engineeering principles to solve
      problems in medicine, such as the design of artificial
      limbs or organs; -- called also biomedical engineering.
      [PJC]

   3. the branch of engineering dealing with the application of
      biological processes to the solution of practical
      problems, such as the manufacture of products by
      fermentation, the production and use of enzymes for
      various purposes, the use of microorganisms in
      environmental cleanup, etc.; -- called also
      biotechnology.
      [PJC]

The Collaborative International Dictionary of English v.0.48:

biotechnology \bi`o*tech*nol"o*gy\ n.
   same as bioengineering.
   [PJC]

WordNet (r) 3.0 (2006):

biotechnology
    n 1: the branch of molecular biology that studies the use of
         microorganisms to perform specific industrial processes;
         "biotechnology produced genetically altered bacteria that
         solved the problem" [syn: biotechnology, biotech]
    2: the branch of engineering science in which biological science
       is used to study the relation between workers and their
       environments [syn: biotechnology, bioengineering,
       ergonomics]