Yes Bitcoin Cash is an altcoin, you can understand if a cryptocurrency created and not is Bitcoin, we will call it's altcoin when listed on exchange, call token when still crowdsale or mining first but not listed on any exchange on crypto world.
Altcoins is a derogatory term. Bitcoin Cash has 0.1% to do with things like EOS or IOTA or AntShares, and 99.9% to do with what Satoshi named Bitcoin. Also, it inherits the same "history", bit by bit, and any coin in this new coin belongs to a person that also owned a bitcoin. Unlike Ethereum, where the dev reserved over 16,000,000 coins for themselves, the developers here reserved 0 for them. Anything out there belongs to the same people that owned bitcoin.