The middle class is any class of people in the middle of a societal hierarchy. In Weberian socio-economic terms, the middle class is the broad group of people in contemporary society who fall socio-economicaly between the working class and upper class.
The common measures of what constitutes middle class vary significantly between cultures. In urban India, for example, a family is considered middle class if it resides in an owner-occupied property. In the United States and Canada many families where the primary income-earner is employed in a blue collar job are considered part of the middle class. Moreover, most North Americans would take issue with a definition of middle-class which excluded the working class, i.e. 'classic Weberian'. (Hard work is generally held in high honour, fairness and equality are common law, and the North American economy was built upon traditionally labour intensive industries.)
Similarly, in the United Kingdom, the term "working class" can be seen as carrying its own cultural status. Here the term middle class implies those people who typically have had a good education, own a family house, and hold a managerial or professional post. Those holding a senior role in a profession or ownership/directorship of a corporation may be regarded as upper middle class, but in England this is as much dependent on background and education. The upper class is generally regarded as the aristocracy and landed gentry; very rich financiers buy country estates in order to qualify. It was commonly held that to join the landed gentry required a distance of least three generations from the time at which money was made (especially if through trade) and that those entering into its rank acquired the manners and mores of those already established.
A persistent source of confusion surrounding the term "middle class" derives predominantly from there being no set criteria for such a definition. From an economic perspective, for example, members of the middle class do not necessarily fall in the middle of a society's income distribution. Instead, middle class salaries tend to be determined by middle class occupations, which in turn are attained by means of middle class values. Thus, individuals who might fall in the middle ground on a societal hierarchy as defined by sociologists do not necessarily fall into a middle ground on an economic hierarchy as defined by economists. As a result, intuitive colloquial and journalistic usage of the term casts a wide net and does not necessarily coincide with an academic sociological or economic definition.