Decentralization
Plain English
Instead of one company or government controlling everything (like Facebook owns your data), decentralization means the control is spread across thousands of independent computers worldwide. No single entity can shut it down, censor it, or control it alone.
Technical
Distribution of authority, control, and data storage across a network of independent nodes rather than a centralized entity. True decentralization requires geographic distribution of validators, client diversity, resistance to censorship, and no single point of failure. Measured by Nakamoto coefficient, validator distribution, and governance structure.