A Satoshi (or “sat” for short) is a unit of Bitcoin currency. One Satoshi is equal to 0.00000001 Bitcoin (BTC).
Named after the creator of Bitcoin, Satoshi Nakamoto, a Satoshi is currently the smallest amount of Bitcoin that can be used and recorded on the blockchain.
Other common units of Bitcoin that you might also come across are:
1 BTC = 1,000,000 uBTC (microbitcoins)
We’ve also got a list of popular cryptocurrency converters here.