Recently there have been many reports on the rising US poverty rates. The US poverty level for 2011 was set at $22,350, total yearly income for a family of four - though the actual number varies from state to state. The sites linked below have charts and more details on the actual poverty specification for different family sizes.
HHS Government site
NY Times 2011 Article on Poverty
Wikipedia Poverty article
Poverty in America is almost exclusively classified by income. Below $22,350 is poor, $25K to $40K working class, above $1M is wealthy or rich, etc. This scale is limited and does not count many factors, including the need to adjust by state, family size and other factors. Below is a new scale to measure people's poorness or wealth. This scale uses time as the determining factor.
1 day - poor.
People that are "1 day poor" literally live day to day. They do not know where their next meal will come from and cannot afford housing. They have no savings and no job, or intermittent, very low paying menial jobs. All money earned goes to filling immediate needs.
1 week - poor.
People in this group may have a regular, or part time, low paying menial job. They literally live paycheck to paycheck. They try to pay the rent but may run out of money by the end of the week/month. Food and rent are the top priorities and can be problematic. Any time they might get sick is a problem because they do not have medical benefits and sickness results in loss of income.
1 month - poor.
People in this category have regular, but low paying (minimum wage) jobs and try to pay their bills. Food and rent are still the top priorities but are generally met each month. They may have a second job (individual) or third job (family). If they lost their primary job (and couldn't find another immediately) they would be "out on the street" in a month or less, as they have virtually no savings or safety net.
2-3 months - poor.
This group includes many dual-earner families with regular jobs that pay above minimum wage. One earner may have a third family job of some kind. Many people fall into this group, although having 3 months savings is a stretch for some. Many people in this group may have barely 1 month in savings.
6 months - poor.
People in this category have well paying "career" jobs (with some benefits) and a little savings. They pay their bills and may be two-income families with both having a job that pays well. They may be contributing to a retirement plan, but actual retirement is a long way off. Losing one or both jobs would mean a frantic hunt to quickly get another job, or their savings would be gone in 3-6 months and they would be in serious danger of falling into one of the previous groups.
1-3 years - poor.
People in this group have very well paying "career" jobs, or two well paying professional jobs for a family, usually both with good benefits. They have some savings and probably a retirement plan (401k) or two and may have started some investments. If one lost their job it would require some serious belt-tightening and a definite job search. If both lost their job they are almost immediately back in the "6 months - poor" group.
5-10 years - poor.
This group is wealthy. People in this group have significant savings and investments, including investment income. They probably own their home outright and may have an additional home. Their wealth may have been inherited or acquired through working at high level, business executive/owner type jobs. Losing a job may provoke an accounting exercise to see if "they have the numbers" to retire or if they want to look for another "opportunity."
20 - 50 years - poor.
This is a "super rich" group. People here certainly own multiple homes. They have significant investment income (7-figure) and really do not need to work. They can afford to send their children to the "best schools" and can significantly help them (set them up) in their careers.
Never will be poor.
This group includes today's billionaires and hundred-millionaires. They have more money than they will ever need. They own multiple homes, have huge investments, own multiple companies and can set up their children for life as soon as they are born.