What is Merkle root?
A single hash in the block header that commits to every transaction in the block, built by hashing transactions together in pairs up a tree.
Because the root depends on every transaction, altering any one of them changes the root and therefore the block hash. The tree structure also allows a compact proof that a specific transaction is in a block without downloading the whole block.
That property is what makes lightweight verification possible for wallets that do not store the full chain.
Related terms
Block
A batch of transactions accepted into the ledger together, produced roughly every ten minutes and limited to…
How it worksHash
A fixed-length fingerprint of arbitrary data. Bitcoin uses SHA-256: the same input always gives the same…
NetworkSPV (simplified payment verification)
Verifying that a transaction is in a block using merkle proofs, without downloading the full chain.
This definition is part of the Bitcoin Logical glossary. For the fuller explanation, start with Learn, or see the live numbers on The Bitcoin Signal.