U.S.Government definition - A family is counted as poor if its pretax money income is below its poverty threshold. Money income does not include noncash benefits such as public housing, Medicaid, employer-provided health insurance and food stamps. The 2012 HHS poverty guideline is $11,170 for an individual or $23,050 for a family of four.
United Nations definition - Fundamentally, poverty is a denial of choices and opportunities, a violation of human dignity. It means lack of basic capacity to participate effectively in society. It means not having enough to feed and clothe a family, not having a school or clinic to go to, not having the land on which to grow one’s food or a job to earn one’s living, not having access to credit. It means insecurity, powerlessness and exclusion of individuals, households and communities. It means susceptibility to violence, and it often implies living in marginal or fragile environments, without access to clean water or sanitation.
Extreme Poverty - World Bank defines extreme poverty as living on less than $1.25(US) per day.