Altcoin is a portmanteau of "alternative” and “coin." It refers to cryptocurrencies (value records) other than Bitcoin. Most of these are based on Bitcoin, and their basic functions are essentially the same as Bitcoin. Over 1500 of these currencies have been created worldwide.
Some of the most well-known altcoins are Litecoin and the Japanese original Monacoin.
Coins used for something other than exchanging the coin for something of value are called "Functional Coins," including Ethereum.