The U.S. Centers for Medicare & Medicaid Services features a glossary of medical insurance terms on its website, HealthCare.gov. The National Association of Insurance Commissioners and AIG provide glossaries of general insurance terms on their respective websites.
HealthCare.gov features terms related to health plans, the Affordable Care Act and medical insurance. Tax-related terms, such as capital gains and net rental income, are also defined.
Insurer AIG provides general and business-related insurance definitions, such as broker-dealer and premium, on its website. The NAIC's glossary features terms pertaining to automobiles, aircraft, boats and homes. It also includes definitions specific to insurance professionals.