I conclude from the discussion that the term "rich" is too vague.

Not that I suggest that everyone adopt these definitions, but I usually use these words in the following meaning:

• Rich -- "financially independent", you don't have to work if you don't want to and still have at least upper-middle-class lifestyle.

• Upper-middle -- not worry about money too much, it's sufficient for comfortable and socially adequate lifestyle, but you need a high-paying job and can't really afford expensive extravagances.

• Middle -- money is kinda OK, you can afford all the necessities and some (but not many) luxuries.

• Lower-middle -- money is tight, you can afford most necessities, but few if any luxuries

• Lower -- Paycheck to paycheck (if you have a job), no reserves, any crisis can thoroughly screw you up.