Medicare 

Medicare Supplement Insurance, or Medigap, is a type of health insurance policy sold by private insurance companies to complement Medicare policies. It covers common gaps in Medicare's standard insurance plans. Insured individuals pay monthly premiums for Medigap policies directly to the insurance provider.

Major Medical 

Health insurance is a contract that requires an insurer to pay some or all of a person's healthcare costs in exchange for a premium. More specifically, health insurance typically pays for medical, surgical, prescription drug, and sometimes dental expenses incurred by the insured. Health insurance can reimburse the insured for expenses incurred from illness or injury, or pay the care provider directly.

It is often included in employer benefit packages as a means of enticing quality employees, with premiums partially covered by the employer but often also deducted from employee paychecks. The cost of health insurance premiums is deductible to the payer, and the benefits received are tax-free.

Major medical health insurance is a term that's generally used to describe comprehensive, robust health coverage. This is in contrast to mini-med plans, fixed indemnity plans, limited benefit plans, and policies that are meant to supplement – rather than replace major medical coverage.