The locking script on a Bitcoin output that defines how it can be spent.

A word-based wallet recovery backup, often using BIP-39; successful restoration can also require a passphrase, derivation paths, and the correct wallet format.

Control of the keys or authorization policy needed to use an on-chain account, with responsibility for protecting and recovering that authority.

A 256-bit hash function from the SHA-2 family. Bitcoin uses it for proof of work and address hashing.

Code deployed on a blockchain that executes deterministically when called.

A contract account with social recovery, spending limits, or sponsored gas, rather than a raw EOA.

A tighter rule set that old nodes still see as valid, so the network can upgrade without a clean split.