Mu

How to spell mu

2 letters · 1 syllable

How to pronounce mu

What does mu mean?

1. nounThe twelfth letter of the Greek alphabet, written M or in lowercase, widely used as a symbol in science and mathematics.

Mu in a sentence

• In the physics formula the coefficient of friction is written as the Greek letter mu.

• The engineer explained that the prefix for one millionth is denoted by mu.

Where does mu come from?

Language of origin: Greek

Mu is the name of the twelfth letter of the Greek alphabet, written as the capital M and the lowercase shape that resembles a curling u. The Greeks did not invent the name from scratch; they inherited it, like most of their letter names, from the Phoenician and wider Semitic alphabet, where the corresponding letter was called mem, meaning 'water', its early picture-sign being a wavy line that suggested rippling water. As the sound and shape passed into Greek the name was smoothed down to the simpler mu. English adopted the Greek letter names wholesale for mathematics and science, where mu serves as the symbol for the prefix 'micro' (one millionth), the coefficient of friction, and many other quantities. The spelling trap is its sheer brevity: just two letters, m and u, pronounced 'mew', which tempts writers to add letters that are not there.

How the word is built

• mu (single indivisible root; the name of the Greek letter, from a Semitic source)