Decentralized finance (DeFi) refers both to the blockchain movement aimed at making traditional financial products and services accessible to everyone globally, as well as the innovative blockchain-powered financial applications designed to make financial intermediaries obsolete.
Some of the innovations DeFi have introduced include decentralized lending and exchange platforms, stablecoins, decentralized derivatives, borderless payments, tokenization, etc., which made way for the expansion of blockchain use cases.
In addition, DeFi applications are completely trustless and permissionless since no single entity is in control of these platforms. Instead, they are powered by smart contracts that automate each transaction made on a blockchain with user-defined parameters. Smart contracts also allow the development of decentralized apps (dapps) that people use in order to perform transactions on DeFi ecosystems.