Social class usually comprising of white-collar (non-manual) workers, lower-level managers, and small business owners, often constituting about one-third of the employed population of a country. Theincome of this class is higher than that of the working-class but lower than that of the upper-middle class (doctors, engineers, lawyers, middle-size business owners) and upper class. 
Read more

USAGE EXAMPLE

The most diverse of all the social classes in America is perhaps the middle class due to the vast range of incomes and occupations that it encompasses.