Microgram
Encyclopedia
In the metric system
Metric system
The metric system is an international decimalised system of measurement. France was first to adopt a metric system, in 1799, and a metric system is now the official system of measurement, used in almost every country in the world...

, a microgram (µg or mcg) is a unit of mass
Mass
Mass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...

equal to one millionth (1/1,000,000) of a gram
Gram
The gram is a metric system unit of mass....

(1 × 10−6), or 1/1000 of a milligram. It is one of the smallest units of mass (or weight) commonly used. The symbol "µg" (mu
Mu (letter)
Carlos Alberto Vives Restrepo is a Grammy Award and three-time Latin Grammy Award winning-Colombian singer, composer and actor.-Biography:...

-g) conforms to the International System of Units
International System of Units
The International System of Units is the modern form of the metric system and is generally a system of units of measurement devised around seven base units and the convenience of the number ten. The older metric system included several groups of units...

and is often used in scientific literature, but the United States-based JCAHO recommends that hospitals do not use this symbol in handwritten orders due to the risk that the symbol µ might be misread as the prefix m, resulting in a thousandfold overdose. The abbreviation mcg is recommended instead.

To type the 'micro' symbol, which is a Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

symbol called mu
Mu (letter)
Carlos Alberto Vives Restrepo is a Grammy Award and three-time Latin Grammy Award winning-Colombian singer, composer and actor.-Biography:...

, in most Windows-based programs hold down the Alt key while typing 2-3-0 on the keypad. On a Mac, hold down the Option key
Option key
The Option key is a modifier key present on Apple keyboards. It is located between the Control key and Command key on a typical Mac keyboard. There are two option keys on modern Mac desktop and notebook keyboards, one on each side of the space bar....

while pressing 'm.' You can also press AltGr + m on most keyboards. Using the font face named "symbol", mu is denoted by a lowercase "m": m.