What is dApp?
Also called: decentralized application, decentralised application, dapp
A dApp is an application whose core logic runs on a public blockchain through smart contracts rather than on a single company server, so its rules and history stay independently verifiable.
In practice
Most dApps pair onchain contracts with a normal web frontend. The part that matters is which half holds the logic: if a team can silently change balances or access rules, the application is not decentralised in any meaningful sense. When you evaluate one, read the deployed contract address, check whether it has been audited, and look at how upgrades are controlled.