The satoshi is the smallest unit of Bitcoin (BTC) and is sometimes abbreviated as a ‘sat.’ It is named after Bitcoin creator Satoshi Nakamoto and has been accepted and employed by Bitcoin users since early 2011. Bitcoin can be divided to 8 decimals, so one satoshi is 0.00000001 Bitcoin. Because it is unwieldy to use so many decimals, it is common to describe smaller amounts of Bitcoin in terms of satoshis or sats. For example, 0.00008521 BTC could be referred to as 8521 satoshis or 8521 sats. Bitcoin transaction fees can often be such small quantities that this term is easier to use.

Other cryptoassets that are priced in terms of Bitcoin are often referred to by their price in satoshis. For example, a coin that trades at a price of 0.00000375 BTC is said to trade at 375 satoshis or sats. Some other cryptocurrencies have adopted a variation of the term satoshi. For example, the smallest unit of Litecoin is called a litoshi.

There have been attempts to find other units in between a satoshi and a whole Bitcoin, but they have not been widely adopted. The term ‘bit’ has been proposed to represent 100 satoshis or 0.00000100 BTC. ‘Millibit’ or mBTC has followed to represent 1000 bits (0.00100000 BTC or 100000 satoshis) which would make 1000 mBTC equal to 1 BTC. Although some examples of this can be seen, it is not widely used. With increasing adoption of Bitcoin and cryptocurrencies in general, it is expected that some new terminology may arise and become popular.