Private key
A secret code that proves ownership of cryptocurrency and allows you to sign transactions. Whoever knows the private key has full control over the funds — it should never be shared with anyone.
See also
Hash
A unique, fixed-length string produced from any input data using a mathematical function. The smallest change to the input completely changes the hash, which is why it is used to verify the integrity of blocks and transactions.
Transaction
A record of a cryptocurrency transfer from one address to another. Once confirmed by the network, a transaction becomes part of the blockchain and can no longer be reversed or altered.
Wallet
Software or a device for storing the private keys that give access to cryptocurrency on the blockchain. The coins themselves are not physically "stored" in the wallet — it only holds the keys needed to control them.
Public key
A cryptographic key from which a wallet address is derived to receive funds. Unlike a private key, it can be safely shared with others — similar to a bank account number.
Seed phrase
A set of 12–24 words from which all of a wallet's private keys can be restored. It is the single most important thing to protect: anyone who knows your seed phrase can take full control of your funds.
Mining
The process of verifying transactions and creating new blocks in Proof-of-Work networks, such as Bitcoin. Miners solve complex computational puzzles and are rewarded with cryptocurrency.