stablecoin
A cryptocurrency designed to hold a fixed value, usually one US dollar, so it can be used for payments rather than speculation.
A stablecoin is a digital token designed not to move in price. Where Bitcoin swings wildly, a stablecoin is meant to be worth exactly one dollar today and one dollar next week, usually because the issuer holds real dollars or short term government debt in reserve to back every token. That stability is the entire point: nobody wants to pay for a coffee with something that might be worth 30 percent less by lunchtime.
They keep appearing in AI news because they are the easiest way to move very small amounts of money between programs, quickly and across borders. That makes them the default plumbing for AI agents that need to pay for services. Worth knowing: how well backed a given stablecoin actually is varies a great deal by issuer.