Here is from wikipedia:
History
The value of a bitcoin in satoshi was decided by Satoshi Nakamoto to be 100 million no later than November 2008.[4]
On November 15, 2010, ribuck proposed that the one hundredth of a bitcoin (0.01 BTC) be called a Satoshi.[6] Four months later he instead suggested that the one hundred millionth unit be called an austrian or a satoshi.[7] The name satoshi caught on, and was widely adopted thereafter.[2]
Usage
So we already have a name for smaller parts of bitcoin that people use. This will start to catch on more and more as fiats fail one by one.