Mining - Blockchain
"Mining" is when computers / nodes in a "blockchain network" help to add transactions, as well as extract new "blocks" in the chain. They do this by solving complex algorithms using computer power. The most well-known cryptocurrency that uses this protocol to maintain the operation of the "blockchain network" is Bitcoin. The protocol that defines the use of computing power / miners to maintain the operation of a "blockchain" is called Proof of Work or PoW.
The miners / computers that perform these algorithms in return receive payment or "rewards" for the work. Payment is made in the form of the relevant "blockchain currency". For Bitcoin, the "mines" would thus receive payment in the form of Bitcoin or BTC.