What is stETH and wstETH?

Could you please explain what stETH and wstETH are? I've heard these terms in the context of cryptocurrencies and decentralized finance, but I'm not quite sure about their exact meanings or how they work. Could you break it down for me in a simple and understandable way? I'm particularly interested in understanding the differences between them and how they are used in various financial applications. Thank you for your help in clarifying these concepts!