Altcoin
An altcoin is any cryptocurrency other than Bitcoin.
Also known as: alt, altcoins
The word means "alternative coin" and covers everything from Ethereum and other large networks to thousands of small tokens. Altcoins tend to move with Bitcoin but more sharply: bigger gains in good times, deeper falls in bad ones.
"Altcoin season" describes a stretch when most altcoins outperform Bitcoin. The correlation matrix shows how closely each of the largest altcoins follows Bitcoin.