The term "cryptocurrency wallet" is often thrown around without people understanding were the actual value is being stored. The real value in any cryptocurrency wallet is the private key. This is essentially the piece of information needed to unlock any value on a blockchain ledger. Whoever controls this key generally defines the kind of a wallet being used and who is at risk of losing the funds.
A cryptocurrency wallet is therefore at it's core just the private key but more generally it's an interface for handling and interacting with a blockchain as well as storing the private key securely.