It's where an entity pays for medical expenses rather than many entities paying for it. I'm for one payer and coverage for all. I don't care how rich or poor anyone is. I'm willing, and always have been, to work contributing to providing equally good healthcare for everyone.
The greedy, on the other hand, want to be able to make a profit off people's health problems; and those greedy ones do not want single-payer in the form of the US government because the people through that government would not be willing to grossly enrich those greedy ones.
It's called socialized medicine: socialism versus capitalism.
I'm for socialism, not capitalism. However, I'm for all people having an equal say and for all people being fully informed, not Leninism or Stalinism, etc. I'm also not a Marxist but a Christian.
Most of the rich capitalists are not for all people having an equal say and being fully informed. That's the problem. They have set things up, usually beginning at the points of many guns bought and paid for via more of the same basic gangsterism, so they control the flow of information and many other things they should not.
I am for all of those greedy ones seeing the light, converting, and volunteering (not being coerced but convicted by their hearts -- developing working consciences) to give and share all in a fully giving-and-sharing economic system, fully democratized, fully informed -- no allowing mammon to buy more say, more power, more control for the few over the many. There's an entire monetary-reform plan behind all of this too in the form of debt-free money (a la United States Notes) and then no money needed at all.
It's very much good versus evil.
The capitalists complain about socialists taking from them, but capitalist are right now taking from the whole public in places such as Greece (if the Greeks allow the privatizers to take over, which was the whole point certain extremely rich ones crashed the system -- not all of the superrich agree with doing that).
France has single-payer and universal coverage. It's healthcare system has been rated #1 in the world, far above the US in terms of good outcomes versus expenditures. The laissez-faire capitalists (usually crony capitalists in disguise), are trying to ruin France's healthcare and other social-welfare state systems because those capitalists are greedy and put themselves above everyone else.