"Wealth refers to those goods that satisfies human wants" Adam Smith
"Economics is the study of man in the ordinary buisness of life. It enquires how he earns his income and how he uses it "Alfred Marshall
"ECONOMICS IS THE SCIENCE WHICH STUDIES HUMAN BEHAVIOUR AS A RELATIONSHIP BETWEEN ENDS AND SCARCE MEANS WHICH HAVE ALTERNATIVE USES."PROF.LIONEL ROBBINS
THIS IS ALL THE COAL WE COULD MINE ALL TOGHETHER
"Economics is the study of how man and society choose ,with or without the use of money , to employ scarce productive resources , which could have alternative uses , to produce various commodities over time and distribute them for consumption now and in the future among various people and groups of society"Prof. Samuelson
GROWTH -ORIENTED DEFINATION
Economic activity refers to those activities which are undertaken to earn a living .For eg: worker working in a factory etc.
Every economy undertakes 3 main economic activities:1) Consumption is an economic activity which deals with the use of goods and services or the satisfaction of human wants.2) Production are those activities which are undertaken to produce goods and services.3) Distribution is the economic activity which studies how income generated is distributed among the factors of production.
Non-economic refer to those activities, which are not concerned with creation of money or wealth .For example , housewife cooking food for her family or a teacher teaching her own son