What is the definition of middle class in hass (humanities and social science) History

In humanities and social science history, the middle class is typically defined as a socio-economic group that falls between the upper class (comprising the wealthiest individuals in society) and the lower class (comprising the poorest individuals in society). The middle class is characterized by individuals who have a moderate level of income, education, and social status, often holding professional or white-collar jobs. The middle class is often seen as representing the majority of the population in many societies and is considered vital for social stability and economic growth.