The Affordable Care Act (ACA): An informal term for the Patient Protection and Affordable Care Act and the Health Care and Education Reconciliation Act of 2010—legislation promoted by President Barack Obama that changed how health insurance functions in the U.S. The ACA expanded eligibility of Medicaid and required most Americans to purchase health insurance. It also set up exchanges in several states so insurers could compete to provide the most cost-effective options for consumers.
Source: The Free Dictionary