The name used by the unknown person or people who designed bitcoin and created its original reference implementation.
Satoshi Nakamoto was heavily involved with the Bitcoin community, and collaborated with them in order to modify the underlying bitcoin protocol. Also credited with the invention of the first blockchain database, which set the foundation for more forms of cryptocurrency to emerge. No one really knows whether Nakamoto is a man, woman, or group of individuals is unknown as well, because the mysterious creator has somehow remained anonymous