When Bitcoin was the only blockchain, there wasn’t much of a distinction between the terms and they were used interchangeably. As the technology matured and a variety of blockchains bloomed, the uses quickly diverged from the pure money aspect. Instead, technologists experimented with ideas like decentralized name registry. Other uses utilized the peer-to-peer aspect to deliver messages in a discrete way. In the end, many of these projects failed to find a good use of the technology. The projects left standing helped demonstrate what was possible with beyond buzzwords.
Contrasted with blockchain, cryptocurrency has to do with the use of tokens based on the distributed ledger technology. Cryptocurrency can be seen as a tool or resource on a blockchain network. Anything dealing with buying, selling, investing, trading, microtipping, or other monetary aspects deals with a blockchain native token or subtoken.
Blockchain is the platform which brings cryptocurrencies into play. The blockchain is the technology that is serves as the distributed ledger that forms the network. This network creates the means for transacting, and enables transferring of value and information.
Cryptocurrencies are the tokens used within these networks to send value and pay for these transactions. Furthermore, you can see them as tool on blockchain, in some cases serving as a resource or utility function. Other times they are used to digitize value of an asset.
Blockchains serve as the basis technology, in which cryptocurrencies are a part of the ecosystem. They go hand in hand, and crypto is often necessary to transact on a blockchain. But without the blockchain, we would not have a means for these transactions to be recorded and transferred.