In blockchain technology, an oracle is a third-party service or agent that provides external information to a smart contract on the blockchain.
An oracle is used to bridge the gap between the on-chain and off-chain worlds by providing the smart contract with access to information outside of the blockchain, such as market prices, weather conditions, or other real-world events. Oracles can be centralized or decentralized, with decentralized oracles being preferred in many cases as they provide a more secure and trustless solution. However, there are still challenges in creating reliable and trustworthy decentralized oracles, as they require mechanisms to ensure the accuracy and integrity of the data they provide.