CEX, short for Centralized Exchange, refers to a type of cryptocurrency exchange that is centralized and controlled by a single entity or company. In a CEX, users deposit their cryptocurrencies onto the exchange's platform and trade with other users on the same platform.

Centralized exchanges typically offer a range of trading tools and services, including order books, order matching algorithms, and advanced charting tools. They also often have lower transaction fees and higher liquidity than decentralized exchanges (DEXs).

However, centralized exchanges also have several disadvantages. They require users to trust the exchange with their funds, as the exchange holds the private keys to the user's cryptocurrencies. This has led to several high-profile hacks and security breaches over the years, which have resulted in significant losses for users. Additionally, centralized exchanges may be subject to government regulations and may require users to complete a Know Your Customer (KYC) process, which can compromise their privacy.

Overall, CEXs and DEXs represent two different approaches to cryptocurrency trading, each with their own advantages and disadvantages. While CEXs have been the dominant model for many years, the rise of DEXs has provided an alternative for users who prioritize decentralization and security.