There are a wide variety of definitions of economics with no univerally accepted definition. Adam Smith

Adam Smith

Adam Smith was a Scottish social philosopher and a pioneer of political economy. One of the key figures of the Scottish Enlightenment, Smith is the author of The Theory of Moral Sentiments and An Inquiry into the Nature and Causes of the Wealth of Nations...

 wrote of economics as being concenred with inquiring into the nature and causes of the wealth of nations. The pessimistic outlook of some of the classical economists following Smith, Malthus in particular, led Thomas Carlyle

Thomas Carlyle

Thomas Carlyle was a Scottish satirical writer, essayist, historian and teacher during the Victorian era.He called economics "the dismal science", wrote articles for the Edinburgh Encyclopedia, and became a controversial social commentator.Coming from a strict Calvinist family, Carlyle was...

 to famously describe economics as the Dismal Science

Dismal Science

"The dismal science" is a derogatory alternative name for economics devised by the Victorian historian Thomas Carlyle in the 19th century. The term is an inversion of the phrase "gay science," meaning "life-enhancing knowledge", a reference to the technical skills of song and verse writing...

. While John Stuart Mill defined Political Economy as:

The science which traces the laws of such of the phenomena of society as arise from the combined operations of mankind for the production of wealth, in so far as those phenomena are not modified by the pursuit of any other object.

More modern definitions include those of Marshall and Robbins. Alfred Marshall

Alfred Marshall

Alfred Marshall was an Englishman and one of the most influential economists of his time. His book, Principles of Economics , was the dominant economic textbook in England for many years...

 famously provided a definition in his textbook Principles of Economics (Marshall)

Principles of Economics (Marshall)

Principles of Economics was a leading political economy or economics textbook of Alfred Marshall , first published in 1890. It ran into many editions and was the standard text for generations of economics students.-Writing:...

Economics is a study of man in the ordinary business of life. It enquires how he gets his income and how he uses it. Thus, it is on the one side, the study of wealth and on the other and more important side, a part of the study of man

But Lionel Robbins

Lionel Robbins

Lionel Charles Robbins, Baron Robbins, FBA was a British economist and head of the economics department at the London School of Economics...

' definition is most noted:

Economics is a science which studies human behaviour as a relationship between ends and scarce means which have alternative uses.

Backhouse and Medina (2009) list a range of definitions included in principles of economics textbooks including those that describe economics as the study of:

• The economy
• The coordination process
• The effects of scarcity
• The science of choice
• How human beings coordinate wants and desires, given the decision-making mechanisms, social customs, and political realities of society
• Human behavior

They argue that concise definitions of economics are likely inadequate because of the range of subjects economist look at (including such a variety as growth, auctions, crime, and religion) and the wide range of methodological approaches being used (these include real analysis, econometrics, laboratory experiments, and historical case studies). They conclude by arguing that this lack of agreement on a definition is not necessarily a problem for the subject. They suggest that the particular definition used may reflect the direction that particular authors see economics evolving in, or the direction they would prefer it evolve in.

Additional sources

Backhouse, R. E., & Medema, S. G. (2008). "economics, definition of," The New Palgrave Dictionary of Economics, 2nd Edition.

Backhouse, R. E., & Medema, S. G. (2009). Defining economics: The long road to acceptance of the Robbins definition. Economica, 76, 805-820.

Bye, R. T. (1939) The Scope and Definition of Economics, The Journal of Political Economy 47 (5), pp. 623-47.

Coase, Ronald H. (1978) Economics and Contiguous Disciplines, The Journal of Legal Studies, Vol. 7, No. 2 Jun., pp. 201-211

Dow, Sheila C. (2002) Economic Methodology: An Inquiry, Oxford University Press