dApp (Decentralized Application)
An application that runs on a decentralized blockchain network rather than being hosted on centralized servers. dApps use smart contracts for their backend logic while providing user-friendly front-end interfaces. They are censorship-resistant and typically open-source, though their performance depends on the underlying blockchain's capabilities.
“Uniswap is a dApp — its trading logic lives in Ethereum smart contracts, while its web interface at app.uniswap.org provides a user-friendly way to interact with those contracts.”
Smart Contract
Self-executing programs stored on a blockchain that automatically enforce the terms of an agreement when predetermined conditions are met. Smart contracts enable trustless transactions without intermediaries because the code, once deployed, executes exactly as written and cannot be altered (unless specifically designed to be upgradeable). They form the foundation of DeFi, NFTs, DAOs, and virtually all dApps.
Ethereum (ETH)
The second-largest cryptocurrency and the most widely used smart contract platform, created by Vitalik Buterin and launched in 2015. Ethereum introduced programmable blockchain functionality, enabling the creation of tokens, DeFi protocols, NFTs, and dApps. In September 2022, Ethereum transitioned from Proof of Work to Proof of Stake ('The Merge'), reducing energy consumption by over 99%.
DeFi (Decentralized Finance)
An ecosystem of financial services built on blockchain networks that operate without traditional intermediaries like banks, brokerages, or insurance companies. DeFi uses smart contracts to provide lending, borrowing, trading, insurance, derivatives, and yield generation in a permissionless, transparent, and composable manner. Anyone with a wallet can participate.
Web3
A vision for the next evolution of the internet built on decentralized blockchain infrastructure, where users own their data, digital assets, and identity rather than relying on centralized platforms. Web3 encompasses DeFi, NFTs, DAOs, decentralized identity, and dApps — aiming to shift power from corporations (Web2) back to individuals through cryptographic ownership and governance.