- Age 16 or older
- Seeking employment
- Not currently employed.
So a person under 16 can never be unemployed according to this definition. Nor can someone with a job who is looking for a better or different job. And a person who is over 16, not working, but not actively looking for work is not considered unemployed. This might include:
- Retired
- Disabled
- Military
- Institutionalized
- Spouse/homemaker
- Tired of looking for a job, which might include e.g. a spouse (of employed person) who would like to find a job, a homeless person, a student, a middle age person living with his parents, etc..
Wikipedia has a nice chart of US unemployment going back to 1890:
This show how high (20%) unemployment became in during the years of the Great Depression. The so-called Great Recession, caused by the financial crash in 2008, is much smaller in comparison, comparable to the unemployment rate of the early 1980s recession (10% unemployment rate).