What is the difference between ETH and WETH?

Could you please explain the fundamental differences between ETH and WETH to me? I've heard they're related, but I'm still a bit hazy on the specific distinctions. Is WETH a derivative of ETH or a completely separate entity? How do they function differently within the crypto ecosystem? Also, are there any advantages or disadvantages to using one over the other? I'm trying to broaden my understanding of these cryptocurrencies and how they fit into the broader financial landscape. Your insights would be greatly appreciated.