This note is a part of my Zettelkasten. What is below might not be complete or accurate. It
is also likely to change often.
Oracles allow Smart Contract access to data outside the Blockchain.
They can trigger success or failure clauses in Smart contracts and act as one of the signatories of the transactions.
A Blockchain oracle is an agent that finds and verifies real-world occurrences and submits this information to a blockchain to be used by smart contracts.
from BlockchainHub