ACA stands for the Affordable Care Act (also known as the Patient Protection and Affordable Care Act), a U.S. federal law signed in 2010 that is popularly nicknamed Obamacare. The law's main goals were to improve the quality of healthcare, expand health insurance coverage to millions of uninsured Americans, and make health insurance more affordable. Key features include expanding Medicaid, creating health insurance exchanges (Marketplaces), prohibiting denial of coverage for pre-existing conditions, and allowing young adults to stay on their parents.

Major Provisions:

• Coverage for Pre-existing Conditions: Insurers can no longer deny coverage or charge more based on pre-existing health conditions.

• Health Insurance Marketplaces: States were required to create or facilitate marketplaces where individuals and small businesses could compare and purchase health insurance plans.

• Medicaid Expansion: Expanded eligibility for Medicaid to cover more low-income adults.

• Essential Health Benefits: Mandates that most health insurance plans must cover a comprehensive set of essential health benefits.

• Coverage for Young Adults: Allows young adults to remain on their parents' health insurance plans until age 26.