What are altcoins? 84 coins above one billion dollars: how they differ from Bitcoin

An altcoin is any cryptocurrency other than Bitcoin. The word is a contraction of "alternative coins", and with that the definition is already complete: there is Bitcoin, and there is everything else. How large this "everything else" is can be put in figures. On October 23, 2026 the alternatives stand for around $1.22 trillion, which is 42.62 percent of the entire crypto market of $2.86 trillion. Only 84 coins carry any notable weight, however, because that is how many clear one billion dollars at all. That makes the term as useful as it is misleading.