Encyclopedia

This Archive aims to provide the glossary terms and docs you need to understand Bitcoin and start building Bitcoin-based applications.

O

OP CHECKMULTISIG

Opcode which returns true if one or more provided signatures (m) sign the correct parts...

Learn More →

OP_RETURN transaction

A transaction type relayed and mined by default in Bitcoin Core 0.9.0 and later that...

Learn More →

Opcode

Operation codes from the Bitcoin Script language which push data or perform functions within a...

Learn More →

Opt-in replace by fee

Replacing one version of an unconfirmed transaction with a different version of the transaction that...

Learn More →

Orphan block

Blocks whose parent block has not been processed by the local node, so they can’t...

Learn More →

Outpoint

The data structure used to refer to a particular transaction output, consisting of a 32-byte...

Learn More →

Output

An output in a transaction which contains two fields: a value field for transferring zero...

Learn More →

Output index

The sequentially-numbered index of outputs in a single transaction starting from 0.

Learn More →

Documentation