A ‘dApp’ is an acronym for a ‘decentralized application.’ dApps are developed on the Ethereum blockchain, which means that although they operate just like regular applications, they are decentralized and therefore more secure.
Once a dApp is implemented on the blockchain, all transactions and operations are also encrypted and recorded on the Ethereum blockchain. This means that they cannot be deleted, and they are incredibly difficult to tamper with. They are also more reliable since transactions are conducted with ETH, even if only indirectly through an app-specific token. As they are stored on a decentralized network, they cannot crash, and all previous transactions are permanently stored on it.