mu

¹ American  

[myoo, moo] / myu, mu /

noun

1. the 12th letter of the Greek alphabet (M, μ).

2. the consonant sound represented by this letter.

3. micron.

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Mu ² American  

[myoo, moo] / myu, mu /

noun

1. another name for Lemuria.

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MU ¹ British  

abbreviation

1. Musicians' Union

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mu ² British  

/ mjuː /

noun

1. the 12th letter in the Greek alphabet (Μ, μ), a consonant, transliterated as m

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mu ³ British  

abbreviation

1. Mauritius

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Etymology

Origin of mu

First recorded in 1895–1900, mu is from the Greek word mŷ

Example Sentences

The studies focus on a group of experimental pain-relieving compounds that act on mu opioid receptors.

From Science Daily • Jan. 6, 2026

However, naltrexone, in both short- and long-acting forms, has the opposite pharmacology: it antagonizes mu receptors, occupying them without activating them.

From Scientific American • Sep. 13, 2023

This part is called il mu, which can be translated as “line dance” or “one dance.”

From New York Times • Jul. 12, 2023

Over the following months, mu spread swiftly in Colombia, fueling a new surge of COVID-19 cases.

From Seattle Times • May 4, 2022

How many different ways could you combine mu shu pancakes and fillings?

From "Little Fires Everywhere" by Celeste Ng