# timelock

URL: https://blockspace.wiki/glossary/timelock/

A rule that holds bitcoin back until a given block height or time. A transaction's `nLockTime` sets the earliest block or time at which it can be accepted into a block. The `OP_CHECKLOCKTIMEVERIFY` opcode (BIP 65) does the same for an output: it makes the output unspendable until some point in the future.

Sources:

- Bitcoin Wiki: NLockTime · https://en.bitcoin.it/wiki/NLockTime
- BIP 65: OP_CHECKLOCKTIMEVERIFY · https://github.com/bitcoin/bips/blob/master/bip-0065.mediawiki

Updated: 2026-10-21