A satoshi (sat) is the smallest unit of Bitcoin, representing 0.00000001 BTC (one hundred millionth of a Bitcoin). It is named after Bitcoin mysterious creator, Satoshi Nakamoto.
Satoshi denominations: 1 satoshi = 0.00000001 BTC, 100 satoshis = 1 microbitcoin, 100,000 satoshis = 1 millibitcoin, and 100,000,000 satoshis = 1 Bitcoin.
Why satoshis matter: Makes Bitcoin more accessible psychologically, easier to price small transactions, useful as unit of account as Bitcoin price rises.
Satoshi Nakamoto: Pseudonymous creator of Bitcoin, published the whitepaper in 2008, launched Bitcoin in 2009, and disappeared from public view in 2011.