mBTC, μBTC, Satasha-what? Denominations for small amounts of Bitcoin.

It took me a long time to find this information when I was first starting out so I wanted to offer it here for anyone interested. 

There is a lot of discussion about the naming of these fractions of bitcoins. Here are the most common. 

• 1 BTC = 1 bitcoin
• 0.01 BTC = 1 cBTC = 1 centibitcoin (also referred to as bitcent)
• 0.001 BTC = 1 mBTC = 1 millibitcoin (also referred to as mbit (pronounced em-bit) or millibit or even bitmill)
• 0.000 001 BTC = 1 μBTC = 1 microbitcoin (also referred to as ubit (pronounced yu-bit) or microbit)

The above follows the accepted international SI prefixes for hundredths, thousandths, and millionths. There are many arguments against the special case of 0.01 BTC since it is unlikely to represent anything meaningful as the Bitcoin economy grows (it certainly won't be the equivalent of 0.01 USD, GBP or EUR). Equally, the inclusion of existing national currency denominations such as "cent", "nickel", "dime", "pence", "pound", "kopek" and so on are to be discouraged; this is a worldwide currency.

One exception is the "satoshi" which is smallest denomination currently possible

• 0.000 000 01 BTC = 1 satoshi (pronounced sa-toh-shee)

which is so named in honour of Satoshi Nakamoto, the pseudonym of the inventor of Bitcoin.

For an overview of all defined units of Bitcoin (including less common and niche units), see the Units section of the Bitcoin wiki

This info was taken from the Bitcoin wiki, which has some great information, but can sometimes be hard to navigate.