 I’ve learned over time  is everybody is rich to somebody. 

My definitions would be 
.1% - money will never run out. They care about $100 more than a poor person. I’ve never seen cheaper people in my life than the Uber wealth. 

Rich - Stupid amounts of money, probably earns 1 mil plus a year but a few bad years and their lifestyle could bring them down quickly. Has all the investments maxed out, Vacations many times a year, buys anything they want. Does not give af about $100

Upper Middle Class - Doesn’t worry about money, can’t spend or buy everything but does a lot. Probably buys a stupid car they don’t need (ahem). Has some investments and children college funds saved. Takes multi vacations a year. Losing $100 is probably a regular occurrence through dumb purchases. $100 will not alter their life at all. 

Middle class - I would say same as above but has to budget pretty well to achieve it. Vacations once or twice a year. Doesn’t buy a stupid car. Losing $100 is frustrating but wouldn’t change their life. 

Working class - Budgets extremely well, if they’re responsible they have emergency fund, they have some small savings doesn’t live paycheck to paycheck but can’t afford a whole lot of luxuries or deviations from the budget. May have some debt they’re paying  off.  Losing $100 would be annoying and probably stop you doing a particular thing but you’d recover ok. 

Poor - paycheck to paycheck, stuck in the viscous cycle of having no money. Probably has debt, no savings, worries about money all the time, has to work multiple jobs and probably still can’t make ends meet. Losing $100 could be the difference between eating or not for the family for a while.