# Merkle-Patricia-trie
*Merkle tree* are Hashes of Hashes, they have the advantage that you can verify only a subtree. Ethereum uses [Modified Merkle Patricia Tries](https://github.com/ethereum/wiki/wiki/Patricia-Tree) for transactions (as well as for state and transaction receipts).
what about *Patricia* ? What does a *trie* mean? And how is it used in Ethereum?
**Trie (also called digital tree, prefix trie or radix trie)**
An ordered tree data structure that is used to store a dynamic set or associative array where the keys are usually strings. A node's position in the tree defines the key with which it is associated.
**Merkle Patricia Trie**
As described [here](https://easythereentropy.wordpress.com/2014/06/04/understanding-the-ethereum-trie/) , the term Merkle implies that
> the root node becomes a cryptographic fingerprint of the entire data structure
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