Medigap
noun [ U ]
INSURANCE uk/ˈmedɪɡæp/ usin the US, private medical insurance that helps to pay for the difference between the amount that the government program Medicare pays and the cost of treatment:
The sharp increases in Medigap insurance premiums are a threatening prospect for older Americans.
Medigap coverage/policies/plans Medical services that are covered by Medigap plans are covered at 100%.