Altcoin
Quick definition
Any cryptocurrency other than Bitcoin โ short for 'alternative coin'.
Altcoin is the catch-all word for every cryptocurrency that isn't Bitcoin, from Ethereum down to thousands of tiny tokens. Some have serious technology behind them; many do not.
Altcoins are generally more volatile and riskier than Bitcoin, and the smaller the coin, the easier its price is to manipulate. Beginners are usually advised to understand Bitcoin first before exploring anything else.