A seed phrase is a sequence of typically 12 or 24 simple words generated when you create a cryptocurrency wallet. This phrase acts as a master key, allowing you to recover your wallet and access your funds if your device is lost or stolen. Anyone who obtains your seed phrase can control your wallet and assets, making it crucial to store it securely and never share it. Seed phrases are widely used in blockchain and cryptocurrency systems as a user-friendly way to back up and restore wallets.