0 any cryptocurrency (= a digital currency that is produced by a public network rather than by a government and uses special codes to keep it secure) that is not bitcoin (= the first cryptocurrency to be established):
Altcoins build on the success of Bitcoin by slightly changing the rules to appeal to different users.
Altcoins use technology called blockchain that allows secure peer-to-peer transactions.
Stephanie Yang of The Wall Street Journal defined altcoins as "alternative digital currencies".
