I think it is not described anywhr....

This judgement depends on mindset and thinking of person to person....

if anybody have defination then am also eager to listen it

Upper Class Status>>> Those people are called upper caste status who does nothing and get all the success like they obtain dummy articleship by their father's contacts, get job by relative's contacts even if in fact they mostly do unethical and immoral things and claim to be the best.

Middle class status>>> Those people have enough resources to live, but they are not as rich as upper class status people. They have to work hard to be succeed. They are ethical and moral people who believe in live and let live.

Lower Class status>>> Those people do not have enough resources to live properly. They have to struggle hard to be succeed.