What's µBTC ?

One Bitcoin (BTC) is a very large sum of money: just now, it's (more or less) 628 US $
So there're other units commonly used for transactions:

0.00000001 BTC = 0.00001 mBTC = 0.01 µBTC

And so:

1 µBTC = 0,000628 US $

1 mBTC = 0,628 US $