The definitions for "unemployed" are very well defined. This is the standard "U3" unemployment number. You count as unemployed if you do not have a job and have

The definitions for "unemployed" are very well defined. This is the standard "U3" unemployment number. You count as unemployed if you do not have a job and have looked for work within the last 4 weeks. There are other unemployment numbers that include people who would work if offered a job but aren't actually looking for one, but that's not the main measure that BLS uses. People that wouldn't take a job even if you offered one to them (like students and early retirees) don't count at all- they don't even show up in the denominator of any of these measures. BLS has the summary of all 6 measures of unemployment at http://www.bls.gov/news.release/empsit.t15.htm http://www.bls.gov/news.release/empsit.t15.htm but I don't think they have the detailed breakdown of any of the other measures.