SSI, or Supplemental Security Income, is a federal program in the United States that provides financial assistance to individuals who are elderly, blind, or disabled and have limited income and resources. The program aims to help these individuals meet their basic needs for food, clothing, and shelter. To qualify for SSI, applicants must meet specific income and resource limits, as well as other eligibility criteria. Payments vary based on individual circumstances and are intended to supplement other income sources, ensuring that recipients can maintain a minimum standard of living.