A question from Yahoo! Answers:
How do you define economics? (Note: i am not asking about the literal definations.)?
The key to defining any discipline is to define problems that are typically solved by its practitioners. Also, defining a broad discipline is usually meaningless. Give me any definition of mathematics, and I will find you at least one branch of mathematics that does not conform to that definition. Same goes for economics.
So instead of defining economics, you should be defining narrowed disciplines within it: the study of prices and profits (microeconomics), the study of national income, inflation, and unemployment (macroeconomics), the study of wealth distribution (political economy), etc.