A cryptocurrency is a digital asset whose ownership is recorded on a blockchain — a shared ledger kept by thousands of independent computers. Nobody can print more units than the rules allow, and nobody needs a bank's permission to send them.
You hold cryptocurrency with a private key, usually stored in a wallet. Whoever controls the key controls the coins, which is both the main benefit and the main risk.
Example
Bitcoin, Ether and Solana are cryptocurrencies; so are thousands of smaller coins and tokens.