Definition of 'Middle Class'
Individuals who fall between the working class and the upper class within a societal hierarchy. In Western cultures, persons in the middle class tend to have a higher proportion of college degrees than those in the working class, have more income available for consumption and may own property. Those in the middle class often are employed as professionals, managers and civil servants.
Investopedia explains 'Middle Class'
The word "middle" may be misleading in that it suggests that those in the middle class have earnings within the middle of the population's income distribution, which may not be the case.
Karl Marx referred to the middle class as part of the bourgeoisie when he described capitalism. The term itself has shifted in meaning over time, having once referred to persons who had the means to rival nobles.