Oracle

In the world of Layer 1 blockchains, events and information that happen off-chain, such as actual real world events, have no way of interacting with the chain. A blockchain oracle is a software program or entity used to provide blockchain smart contracts with external data by serving as a data bridge between the blockchain and the real world. When a smart contract requires off-chain external data, these chain oracles are used to provide the necessary data. For example, let’s say that an Ethereum DeFi smart contract involves data related to an off-chain event such as an election or the price of a stock market security, an oracle would be required to introduce this information into the smart contract.