A social class is a set of concepts in the social sciences and political theory centered on models of social stratification which occurs in class society, in which people are grouped into a set of hierarchical social categories, the most common being the upper, middle and lower classes.
"Class" is a subject of analysis for sociologists, political scientists, anthropologists and social historians. However, there is not a consensus on a definition of "class" and the term has a wide range of sometimes conflicting meanings. Some people argue that due to social mobility, class boundaries do not exist. In common parlance, the term "social class" is usually synonymous with "socio-economic class", defined as "people having the same social, economic, cultural, political or educational status", e.g., "the working class"; "an emerging professional class". However, academics distinguish social class and socioeconomic status, with the former referring to one's relatively stable sociocultural background and the latter referring to one's current social and economic situation and consequently being more changeable over time.
The precise measurements of what determines social class in society have varied over time. Karl Marx thought "class" was defined by one's relationship to the means of production (their relations of production). His simple understanding of classes in modern capitalist society is the proletariat, those who work but do not own the means of production; and the bourgeoisie, those who invest and live off the surplus generated by the proletariat's operation of the means of production. This contrasts with the view of the sociologist Max Weber, who argued "class" is determined by economic position, in contrast to "social status" or "Stand" which is determined by social prestige rather than simply just relations of production. The term "class" is etymologically derived from the Latin classis, which was used by census takers to categorize citizens by wealth in order to determine military service obligations.
In the late 18th century, the term "class" began to replace classifications such as estates, rank and orders as the primary means of organizing society into hierarchical divisions. This corresponded to a general decrease in significance ascribed to hereditary characteristics and increase in the significance of wealth and income as indicators of position in the social hierarchy.