is "any government system that provides monetary assistance to people with an inadequate or no income." In the United States, this is usually called welfare or a social safety net, especially when talking about Canada and European countries.
Social security is asserted in Article 22 of the Universal Declaration of Human Rights, which states:
Everyone, as a member of society, has the right to social security and is entitled to realization, through national effort and international co-operation and in accordance with the organization and resources of each State, of the economic, social and cultural rights indispensable for his dignity and the free development of his personality.
In simple terms, the signatories agree that the society in which a person lives should help them to develop and to make the most of all the advantages (culture, work, social welfare) which are offered to them in the country.
Social security may also refer to the action programs of an organization intended to promote the welfare of the population through assistance measures guaranteeing access to sufficient resources for food and shelter and to promote health and well-being for the population at large and potentially vulnerable segments such as children, the elderly, the sick and the unemployed. Services providing social security are often called social services.