A stale block is a block or unit of a miner's work that has lost relevance because the network or pool has already accepted another result. Such work brings no reward.

Slippage is the difference between the expected and the actual execution price of an order on a cryptocurrency exchange. It arises from market movement and a lack of liquidity.

A payment service provider (Payment Service Provider, PSP) is a service that allows payments to be accepted and sent by various methods, combining many payment methods in a single interface for businesses and users.

A private key (private key) is a secret string that gives control over a cryptocurrency wallet and allows transactions to be signed. Its loss or disclosure means the loss of access to funds.

Premining (premine) is the mining of part of the coins by a cryptocurrency's creators before its public launch. It can be used transparently to fund the project or serve as a tool for abuse and manipulation.