I have no problem with BitPay trying to popularize 1µBTC as the most common unit for accounting. However, their choice of short name leaves something to be desired.
This.
The rational is allowing Bitcoin to operate on most financial software without too much fixing. They almost assume a decimal with two places for currency. Satoshis are the cents or after the decimal. 100 satoshi in a whole unit they call bit a "mike"
FTFY.