PPP here is a way of paying for big public things — roads, trains, hospitals, schools — where the government does not put in all the money. Private companies put money in too, and they often build or run the project for many years. The public side wants the hospital or the road to exist for everyone; the private side wants to earn its money back. Though actually, people argue a lot about whether this is a good deal. It can get a building up faster, but the public may pay more over the long run, and it is not always clear who is in charge when something goes wrong. You will meet it in news about infrastructure and in government papers. It is a formal, technical label, not kitchen talk. And the same three letters are used for other things: in economics class, PPP often means purchasing power parity, a way of comparing money across countries. This entry is only the building-and-funding system.