Bitcoin Cash (BCH) is hard fork (a community-activated update to the protocol or code) of Bitcoin that took effect on August 1st, 2017 that increased the block size to 8MB, to help the scale the underlying technology of Bitcoin.Nov 16th 2018: BCH was hard forked again and split into Bitcoin SV and Bitcoin ABC. Bitcoin ABC became the dominant chain and took over the BCH ticker as it had more hashpower and majority of the nodes in the network.
There are two factions of bitcoin supporters, that support large blocks or small blocks. The Bitcoin Cash faction favors the use of its currency as a medium of exchange for commerce while the Bitcoin-supporting faction view bitcoin's primary use as that of a store of value. Some Bitcoin supporters like to call Bitcoin Cash “Bcash,” “Btrash,” or simply a scam, while Bitcoin Cash advocates insist that their implementation is the pure form of Bitcoin.
Peer to peer (P2P) electronic cash is simply described as online money sent from one person to another without the need for a trusted third-party. As described in the original Bitcoin whitepaper by Satoshi Nakamoto, P2P cash makes use of digital signatures as part of the solution, but the main benefits are lost if a trusted third party is still required to prevent fraud. This makes P2P cash a trustless and safe way to transact without the need of intermediaries.