# Oracle

> A service that brings outside information, like prices or sports scores, onto a blockchain.

Canonical URL: https://business.fudfomo.co/glossary/oracle
Source: What The Block! Dictionary v1.0 (last updated 2026-04-25), browsable at https://wtb.fudfomo.co.

## Definition

An oracle is a service that feeds real-world data into smart contracts. Blockchains by themselves cannot see external information, so contracts that need to react to a price, a weather event, or a sports result rely on oracles.

A bad or manipulated oracle can break a contract that depends on it. Major DeFi protocols spend a lot of effort choosing oracle providers and combining several feeds for safety.

## Related terms

- [Smart Contract](https://business.fudfomo.co/glossary/smart-contract): A program that runs on a blockchain and does what it says, automatically.
- [DeFi](https://business.fudfomo.co/glossary/defi): Decentralised finance. Apps that offer lending, trading, and saving on a blockchain instead of through a bank.
- [DEX](https://business.fudfomo.co/glossary/dex): A decentralised exchange. Trade crypto directly from your wallet, without an account.

## See the full catalogue

What The Block! covers more than 2,000 plain-English crypto terms, delivered as embeddable hover-state tooltips for crypto exchanges. https://wtb.fudfomo.co