The satoshi is known as the smallest denomination of Bitcoin, named after Satoshi Nakamoto, the pseudonymous creator(s) of Bitcoin. The ratio of satoshis to Bitcoin is 100 million satoshis to one Bitcoin.
As Bitcoin’s value increased significantly, smaller denominations became necessary for smaller transactions. These smaller denominations made Bitcoin transactions more convenient and readable.
According to the Bitcoin protocol, a single Bitcoin cannot be divided further than 1 satoshi.