Crypto glossary
BIP-39 wordlist
BIP-39 is the standard that turns random entropy into a 12- or 24-word seed phrase using a fixed list of 2,048 words with a built-in checksum.
Published in 2013, BIP-39 takes 128 to 256 bits of entropy, adds a short checksum derived from its hash and splits the result into 11-bit chunks. Each chunk selects one word from a list of 2,048, so 128 bits plus a 4-bit checksum becomes 12 words and 256 bits plus 8 becomes 24. The phrase, optionally combined with a passphrase, is then stretched into the master seed of an HD wallet.
The English wordlist was chosen so that the first four letters of each word are unique, making it easy to write down and recover even from abbreviations. Official lists exist in other languages, including Spanish, though most wallets only support English. Nearly every modern wallet, on Bitcoin, Ethereum and most other chains, uses BIP-39, which is why one phrase can be restored in different apps.
Because the last word contains checksum bits, not every combination of words is valid, which helps catch typos. The standard says nothing about which derivation paths to use, so restoring a phrase in another wallet can show an empty balance until the right path is selected. Anyone with the words controls the funds.
Example
A user restoring a wallet types 12 words; the app rejects them because the checksum fails, revealing that one word was copied wrongly from the backup card.