What is a definition of economics for? Why would we want  
one? 
  For a dictionary definition, see a dictionary, or observe  
how the word is actually used. Both might give confusing  
results, but that reflects actual usage. 
  Possibly more enlightening - try to find out who is  
generally counted as an economist (supplementary question:  
by whom?) and observe what they do. Or observe journals  
generally counted as economics journals (by library  
classification? weighted by some means, such as citation  
counts?) and see what they publish. Or look at research  
funding (history of economics would pretty well vanish by  
that criterion!). 
  That would tell you what economics actually is, not what  
someone thinks it ought to be. Do something similar for past  
periods to find out what economics used to be. Making up  
definitions, possibly to reflect some idea of what you wish  
your colleagues were doing, is fun, but does it get us  
anywhere? 
  Tony Brewer, University of Bristol ([log in to unmask])