What does USDT mean in money?

Excuse me, could you please explain to me the meaning of USDT in the context of money and finance? I've heard the term being used frequently in cryptocurrency circles, but I'm not entirely clear on its significance or purpose. Is it a specific type of currency? Or is it related to a certain trading or investment strategy? I'd appreciate it if you could provide a concise and easy-to-understand explanation of what USDT stands for and how it's used in the world of finance. Thank you in advance for your help.