This is how Vitalik initially described oracles, as far as I know: https://blog.ethereum.org/2014/07/22/ethereum-and-oracles/ https://blog.ethereum.org/2014/07/

This is how Vitalik initially described oracles, as far as I know: https://blog.ethereum.org/2014/07/22/ethereum-and-oracles/ https://blog.ethereum.org/2014/07/22/ethereum-and-oracles/ The terminology seems to have changed to mean any system that provides external data to ethereum contracts.