# Merkle Tree

> A way of summarising many pieces of data into a single hash, used to prove a single piece of data is in the set.

Canonical URL: https://fudfomo.co/glossary/merkle-tree
Source: What The Block! Dictionary v1.0 (last updated 2026-04-25), browsable at https://wtb.fudfomo.co.

## Definition

A Merkle tree is a tree of hashes. Pairs of data are hashed together, then those hashes are paired and hashed again, and so on, all the way up to a single root hash.

Anyone with the root and a small number of intermediate hashes can prove a piece of data was part of the original set without needing the full set. Blockchains use Merkle trees to summarise transactions and account states efficiently.

## Related terms

- [Hash](https://fudfomo.co/glossary/hash): A short fingerprint of any piece of data, produced by a one-way mathematical function.
- [Block](https://fudfomo.co/glossary/block): A bundle of transactions added to a blockchain together.
- [Blockchain](https://fudfomo.co/glossary/blockchain): A shared digital record of transactions that no single person or company controls. Everyone can read it, and changes are extremely hard to fake.

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