Bitcoin Cash is a hard fork of the original Bitcoin network, which is just a technical term that means Bitcoin Cash broke away from Bitcoin and established itself as its own independent network.

Bitcoin Cash did this in order to make improvements to the network, the most notable of which was increasing the block size from 1MB to 8MB, which drastically improves transaction speed, reduces transaction fees, and makes Bitcoin Cash a much more scalable digital currency in terms of the volume of transactions the BCH network can handle.

Today, the original Bitcoin network is still the world's largest cryptocurrency and is viewed by many as a long-term store of value, rather than a digital medium for daily transactions, whereas Bitcoin Cash seeks to be used as a scalable day-to-day digital currency.