What Is a “Sat” (Satoshis) and What Is Its Significance?
A satoshi, or "sat," is the smallest unit of Bitcoin, representing one hundred millionth of a single Bitcoin (0.00000001 BTC). It is the base unit of account used for calculating transaction fees and the fee rate (sat/vB).
Its significance lies in enabling micro-transactions and providing a granular unit for expressing value in the Bitcoin economy.