What is a 'Satoshi'? I am aware that Satoshi Nakamoto is the author of the paper that originated Bitcoin and the creator of the original bitcoin client. However, I often hear the term Satoshi as if it was a monetary unit.

What is a Satoshi?
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