By definition, altcoins are “alternative coins.” The term applies to literally all cryptocurrencies that are not Bitcoin. Popular altcoin examples include Ethereum, Litecoin, Ripple, Tron, Verge, EOS, and all others.
Many altcoins are just straight-out copies (forks) of Bitcoins’ open-source protocol. Others are merely cash-grab projects or failed experiments. Despite that, there also are many exciting ventures with unique value propositions, solutions, and characteristics. You just need to sort the wheat from the chaff.
Digital currencies, also known as cryptocurrencies, digital coins, or currency tokens, are designed to facilitate quick and reliable peer-to-peer transactions. Bitcoin and number of alternatives fall under this category. If fact, many of them came to exist simply by modifying Bitcoin’s core code. Such coins are Litecoin, Bitcoin Cash, Dash, Zcash, and many others. Other digital currencies are written from scratch. Coins like Monero, Bytecoin, Ripple, Stellar, Nano, and similar projects still serve the same goal, but use different approaches.