This document provides an overview of decentralized finance (DeFi). It defines DeFi as blockchain-based decentralized applications for financial services that generally replace traditional intermediaries. DeFi aims to reconstruct financial services using distributed ledger technology, digital assets, and smart contracts. The document outlines four key characteristics of DeFi: 1) it provides financial services/products, 2) operates with minimized trust in intermediaries through settlement on blockchain, 3) has a non-custodial design, and 4) has a programmable, open, and composable architecture. It also notes that the degree to which projects exhibit these characteristics can vary and change over time.