Ethereum

Bitcoin is the most famous cryptocurrency. If your grandma has heard of one cryptocurrency, it's Bitcoin. If she's heard of two (and what are the odds of that?), the other one is probably Ethereum.

If Bitcoin is The Beatles of the crypto world, then Ethereum is something like the Kinks, or maybe the Who. (Bitcoin has such control of the public imagination that there's probably no equivalent to the Rolling Stones.)

Ethereum is the name of a computing platform. It provides the basis of the currency, which some pedants might tell you has the official name of "Ether," though common usage usually refers to the currency as "Ethereum" as well. As with Bitcoin, the basic structure of Etherium is based on blockchain, though the nuts and bolts of how they work are different.