Bitcoin Cash (BCH) is a cryptocurrency created via a fork of the Bitcoin network. This means that any user who held Bitcoin at the time of the fork (August 1st, 2017), now has an equivalent amount of Bitcoin Cash on the forked Bitcoin Cash blockchain.
Bitcoin Cash was created as an answer to the years-long debate among the Bitcoin community regarding the best way to scale Bitcoin to more users. The most simple solution, and the one adopted by Bitcoin Cash, is to increase the Max Blocksize Limit parameter of the Bitcoin codebase. While Bitcoin’s block size limit remains at one megabyte (allowing for ~250,000 transactions per day), Bitcoin Cash has increased the limit to 8MB, allowing for around two million transactions to be processed per day. As far as the users of Bitcoin/Bitcoin Cash are concerned there is very little noticeable difference on the frontend when using either currency. The main difference between these coins is the fact that, given equal hashrate, BCH protocol allows for more transactions per second which translates to faster payments and lower fees.
There are some who oppose the existence of Bitcoin Cash for personal reasons and wish to undermine it as a viable alternative to Bitcoin. Instead of offering a technical or economic critique of Bitcoin Cash these people refer to Bitcoin Cash as “bcash” on social media in hopes that this nickname will lead to confusion and diminish adoption rates. If your wallet or exchange uses the term “bcash” they are likely referring to Bitcoin Cash; but, it should be noted that "bcash" is not the proper name, nor a commonly used abbreviation of Bitcoin Cash, and is a hostile attempt to confuse users. It would be best to proceed with caution when dealing with anyone who would use the term "bcash" instead of the currency's actual name, Bitcoin Cash.
Whether you decide to use Bitcoin Cash or not is entirely up to you. While Bitcoin currently has a larger network and supporting infrastructure, many are dismayed by the ever-increasing fees and long transaction times. Bitcoin Cash offers lower fees and a more reliable rate of transaction than Bitcoin. In terms of development, most of the code for Bitcoin Cash is the exact same as Bitcoin's. This makes developing software or altering existing software to support Bitcoin Cash quite simple.
Here are some of the many exchanges that support Bitcoin Cash (BCH):