Cryptocurrency, sometimes called crypto, is any form of currency that exists digitally or virtually and uses cryptography to secure transactions. Cryptocurrencies don't have a central issuing or regulating authority, instead using a decentralized system (see 'What is blockchain?') to record transactions and issue new units.
Cryptocurrencies are exchanged through transactions from one user’s wallet to another’s. This is done by sending cryptocurrency to a specific wallet address (see ‘What is a wallet? Why do I need one?’) which all occurs on the blockchain.