Understanding cryptocurrency is not difficult and once the proper knowledge of cryptocurrency is gotten, how the blockchain works will be easier to grasp.
Cryptocurrency is a form of encrypted money that works by encryption. Cryptocurrencies run on a distributed public ledger called blockchain, a record of all transactions updated and held by currency holders.
Blockchain is a system in which a record of transactions made in bitcoin or another cryptocurrency are maintained across several computers that are linked in a peer-to-peer network. The blockchain is like a logbook keeping the record of every activity of a cryptocurrency and by virtue of its nature, it is used to keep records of other things aside from cryptocurrencies, such as medical records, storage of data and information of organisations etc.
Hence it's safe to say cryptocurrency under the blockchain, since cryptocurrencies can't work without the blockchain, but a blockchain can work without a cryptocurrency.