The essence of the term oligarchy is captured by the briefest of descriptions as ‘rule of the few’. But the vagueness and uncertainty of the term are highlighted when trying to define who exactly the few are. Originally the term applied to rule by a local lord or family whose wealth allowed power over local decisions, but as populations, state machinery and national integration grew, the power and wealth of some families and business sectors grew disproportionately.
The sector of activity in which the oligarchy is involved varies from country to country. It may include specific productive sectors of a country such as plantation agriculture, logging or mining; the business sector may be dominated by foreign interests rather than national; the church may wield significant power over local populations; or some families may have benefitted from a history of financial dealings from which they have accrued enormous wealth.
In his important work on ‘The Political Economy of Central America since 1920’, Victor Bulmer-Thomas explains how a traditional élite of small merchants and landowners had been replaced by the 1920s by a powerful new élite, based largely on the export sector as growers, traders or financiers (particularly of coffee). The success of this new élite had been so great that
the new interests came to form a virtual oligarchy exercising economic, social and political influence out of all proportion to their numbers. The new élite absorbed foreigners into its midst without losing its national character and demanded from the state changes in legislation to guarantee an adequate supply of land and labour for the expansion of the export sector.
The close links between the US government, US transnational companies and Central American oligarchies, resulting from a history of US involvement in and control of the Central American economy and military, are explored in other parts of this chapter.
 Victor Bulmer-Thomas (1987) The Political Economy of Central America since 1920, Cambridge: Cambridge University Press.
 Ibid., p.2.