Is tether USDT a stable coin?

Could you please elaborate on the question: "Is tether USDT considered a stable coin?" I'm particularly interested in understanding its stability mechanisms and how it differs from other cryptocurrencies. Also, could you discuss its role in the cryptocurrency ecosystem and the reasons why it might be considered a stable coin? Furthermore, I'm curious about its popularity among investors and how its price has fluctuated compared to traditional fiat currencies. Could you provide some insights into these aspects?