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.

---

Mu ² American  

[myoo, moo] / myu, mu /

noun

1. another name for Lemuria.

---

MU ¹ British  

abbreviation

1. Musicians' Union

---

mu ² British  

/ mjuː /

noun

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

---

mu ³ British  

abbreviation

1. Mauritius

---

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

Delta overtook several immune-evasive variants besides mu, including beta, gamma and lambda.

From Seattle Times • May 4, 2022

The previous afternoon, Lopsang had exhausted himself carrying a satellite phone for Pittman, in addition to the rest of his mil mu ix in load, from Camp Three to Camp Four.

From "Into Thin Air" by Jon Krakauer