[middle class] n (1766): a class occupying a position between the upper class and the lower class; esp: a fluid heterogeneous socioeconomic grouping composed principally of business and professional people, bureaucrats, and some farmers and skilled workers sharing common social characteristics and values
MIDDLE CLASS
Meaning of MIDDLE CLASS in English
Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012