Regarding heterodox economics, the first definition I encountered on my brief google
search was the following:
  
"By heterodox economics, we mean Marxism, Institutionalism, Social Economics, Post
Keynesian Economics, Sraffian Economics, Feminist Economics, Georgist Economics,
Evolutionary Economics, Historical Economics, and Austrian Economics."
  
http://www.economicsbulletin.uiuc.edu/Abstract.asp?PaperID=EB-01CC0030  
  
There are, of course, papers on the history of most if not all of these subjects, as the
major writers in the respective fields define them. It seems to me, however, that with
perhaps minor exceptions, each of these uses choice theory as a central part of its
applied work. Consider, for example, evolutionary economics. Do not writers in this field
regard humans as beings that are very distinct from even the highest of the higher
animals? And is not that distinguishing feature the human ability to choose? More
specifically, isn't the distinguishing feature the ability to identify alternatives and
choose among them in the way that individuals regard as most suitable? True, the
evolutionary economist would probably also want to write about the formation of values, or
criteria of choice and even of the way in which the ability to choose itself evolved. And
he would want to write about money exchange. But choice itself is, it seems to me, the
element that distinguishes evolutionary economics from evolutionary biology and from the
study of evolution proper.
  
Pat Gunning