Below, a brief summary of Bitcoin Units:
A Satoshi is the smallest fraction of a Bitcoin that can currently be sent: 0.00000001 BTC, that is, a hundredth of a millionth BTC.
In the future, however, the protocol may be updated to allow further subdivisions, should they be needed.
Further examples of units
•1 BTC = 1,000 mBTC (millibitcoin)
•1 BTC = 1,000,000 μBTC (microbitcoin)
•1 BTC = 100,000,000 Satoshis
•1 mBTC = 100,000 Satoshis
•1 μBTC (microbitcoin) = 100 Satoshis
You only cover a part of existing units. There are also kBTC, hBTC, dBTC and cBTC. A explanation is provided on the following blog article I recently found
https://cryptovoyager.wordpress.com/2019/10/19/the-units-in-bitcoin-a-detailed-explanation/
