What is a beneficiary?
A beneficiary, in terms of Medicare, simply refers to a person who is enrolled in Medicare Part A and/or Part B. The term “Medicare enrollee” means the same thing as Medicare beneficiary.
There is sometimes confusion around the word “entitled” when it comes to Medicare. Specifically, if a person is “entitled to Medicare,” that means they’re both eligible for and enrolled in at least Medicare Part A. If they are eligible but have not enrolled, they are not considered “entitled” to Medicare.
Medicare Part B is different, as it requires a monthly premium, and people who are eligible for Part B can reject it without having to also reject their Social Security benefits (as would be the case if they rejected Part A). This is why you’ll see references to someone being “entitled to Medicare Part A” but “enrolled in Medicare Part B.” But both of those terms describe a person who has Medicare coverage.
So the federal definition of Medicare beneficiary as “an individual who is entitled to benefits under part A… or enrolled under part B…” simply means a person who has coverage under Medicare Part A and/or Medicare Part B.
Footnotes