Cryptocurrency is a form of payment that can be exchanged online for goods and services. Many companies have issued their own currencies, often called tokens, and these can be traded specifically for the goods or services that the company provides. Cryptocurrencies work using a technology called blockchain. Blockchain is a decentralized technology spread across many computers that manages and records transactions.
In our glossary, we also include some information on several common terms used in the game: https://gamebook.planetix.com/resources/game-economy/glossary
Further reading (External links - we are not responsible for the information): https://www.pwc.com/us/en/industries/financial-services/fintech/bitcoin-blockchain-cryptocurrency.html