Bitcoin is a digital currency that was created by Satoshi Nakamoto in 2009.It is created electronically and impossible to control it.This currency are not printed currency like dollars or euros.Running computer all around the world are producing it.Owing to this reason they are different from other currencies.
The difference of bitcoin from other crypto currencies is,bitcoin has a 21,000,000 supply and it is the first altcoin being invented and it has a volatiles price highest from other altcoin, while altcoin is alternate of bitcoin.