CEX stands for Centralized Exchange, which is a cryptocurrency exchange that operates on a centralized platform and is controlled by a centralized authority or entity. CEXs require users to deposit their assets with the exchange, which then facilitates the buying and selling of cryptocurrencies on behalf of the users. They are often more user-friendly and provide greater liquidity compared to DEXs, but also pose a higher risk of hacking or theft of user assets due to their centralized nature.