What is the difference among BTC, mBTC and uBTC?

BTC stands for Bitcoin, and it is the actual currency. mBTC and uBTC are simply different ways to view it.
mBTC is a thousandth of a Bitcoin, whilst uBTC is a millionth of a Bitcoin.


BTC = 1 Whole Bitcoin
mBTC = 0.001 BTC
uBTC = 0.000001 BTC