Is USDT equal to USDC?

Excuse me, I'm a bit confused about something regarding cryptocurrencies. Could you please clarify for me if USDT is the same as USDC? I've heard both terms being used interchangeably in some contexts, but I'm not entirely sure if they refer to the same thing. Could you explain the difference, if any, between these two? I'm interested in understanding the nuances of these cryptocurrencies and how they function in the market. Thank you for your time and assistance in clarifying this matter for me.