An altcoin is any cryptocurrency other than Bitcoin. The word altcoin is a combination of two words: “alternative” or “alt” and “coin.” Together, they create the category of cryptocurrency that is alternative to Bitcoin. Alternative currencies aim to serve different niche markets not yet addressed by Bitcoin.
There are approximately 1600 altcoins in the market today actively being traded on a variety of cryptocurrency exchanges. Until December 2017, Bitcoin made up more than 50 percent of the total market capitalization of cryptocurrency. That ratio has changed dramatically in 2018 as the growth of altcoins in number and valuation increases. Because of their growth, Bitcoin’s market domination — or percentage of total market capitalization — is hovering around 35 percent.
Examples of altcoins include Ethereum, Litecoin (which was the first altcoin back in 2011), Monero, Dash, Zcash, Ripple, Stellar Lumen, NEO, and Cardano. Many altcoins are tokens built on the Ethereum blockchain such as Augur, Golem, OmiseGo, Civic, and Cindicator.