middle class

Short definition from Wiktionary

Noun

1. 1
   A social and economic class lying above the working class and below the upper class.
2. 2
   The groups in society composed of professionals, semi-professionals, and lower to middle managerial level workers.

Adjective

1. 1
   Occupying a position between the upper class and the working class.
2. 2
   Characteristic of the middle class(es); reflective of that class's values and aspirations. Commonly associated with a desire for social respectability and an emphasis on family values and education.