The twelfth letter of the Greek Alphabet, between lambda and nu. Used as the symbol of choice in physics to represent coefficients of friction, and the subatomic particles muons, among other things.

"Mu" is the Japanese pronunciation of the Chinese ideograph "Wu." The term does not mean "no thing". It means "does not have" or "without".

Mu aka multiple unit. A term for railroad cars that are linked together, self propelled, and have a control cab in the front of the vehicals. Many commuter trains, and just about all mass transit trains are Mu's.

I'm surprised no-one put it like this: MU is simply a human term for null. This isn't exact, but seems to be as good as it gets.

Here is an ASCII mu (the kanji):

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         %%"   %%%%    %%%%    %%%%    %%%%
       ,%"     %%%%    %%%%    %%%%    %%%%
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               %%%%    %%%%    %%%%    %%%%     ,%%,
     "%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
               %%%%    %%%%    %%%%    %%%%
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               %%%%    %%%%    %%%%    %%%%    ,%%,
      "%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%


          "%,       "%%,,      ""%%,,     ""%%,,
           %%%        %%%%,       %%%%,      "%%%%,
         ,%%%%%        %%%%%      "%%%%%      "%%%%%,
        %%%%%%%        %%%%%%      %%%%%%      "%%%%%
        "%%%%"          "%%%"       "%%%"       "%%%"

(And for those with browsers that can show unicode: 無)

Short for (somehow) the University of Missouri at Columbia, or Mizzou. I'm not sure how UMC can be changed to MU without changing the word order, but even road signs point it out as such.

Physics joke:

Question: Two cats are on a steeply pitched roof. Which one will stay up the longest?

Answer: The one with the highest mu! Coefficient of friction

Mu is also the Standard SI prefixes for "micro-," or 10^-6. That's a mu--µ--not "mc." If you don't know how to make a mu, you have no business measuring quantities that small.

"You can not kill that which does not exist" (Buddhist saying). Mu means emptiness in Japanese and it describes a state of being in which the person who has obtained it projects neither sakki nor fear. At this time they become imposible to strike down as one must return your sakki before you can attack. Only another who has also attained Mu can slay them.

The path to obtaining Mu is described in Dark Horse's "Lone wolf and cub" as follows, "Met the Buddha, kill the Buddha. Meet your parents, kill your parents" (every 14 year old's dream I'm sure). Essentially one who has obtained Mu has conquered their fear of dying.

mu /moo/

The correct answer to the classic trick question "Have you stopped beating your wife yet?". Assuming that you have no wife or you have never beaten your wife, the answer "yes" is wrong because it implies that you used to beat your wife and then stopped, but "no" is worse because it suggests that you have one and are still beating her. According to various Discordians and Douglas Hofstadter the correct answer is usually "mu", a Japanese word alleged to mean "Your question cannot be answered because it depends on incorrect assumptions". Hackers tend to be sensitive to logical inadequacies in language, and many have adopted this suggestion with enthusiasm. The word `mu' is actually from Chinese, meaning `nothing'; it is used in mainstream Japanese in that sense. Native speakers do not recognize the Discordian question-denying use, which almost certainly derives from overgeneralization of the answer in the following well-known Rinzai Zen koan:

A monk asked Joshu, "Does a dog have the Buddha nature?" Joshu retorted, "Mu!"

See also has the X nature, Some AI Koans, and Douglas Hofstadter's "Gödel, Escher, Bach: An Eternal Golden Braid" (pointer in the Bibliography in Appendix C.

--The Jargon File version 4.3.1, ed. ESR, autonoded by rescdsk.

"Because we're unaccustomed to it, we don't usually see that there's a third possible logical term equal to yes or no which is capable of expanding our understanding in an unrecognisable direction. We don't even have a term for it, so I'll have to use the Japanese 'mu'.

mu means 'no thing'. Like 'quality' it points outside the process of dualistic discrimination. mu simply says, 'no class; not one, not zero, not yes, not no'.

It states that the context of the question is such that a yes or no answer is in error and should not be given. 'Unask the question' is what it says."

---

- Robert M. Pirsig from Zen and the Art of Motorcycle Maintenance.

mu is also a sub-culture magazine, based in Perth, Australia. It's refreshing and very very innovative, all a mishmash of textures and texts and sprawling, experimental pieces; my favourite, though it is never produced as regularly as I like. It's a very eclectic mix of music, culture, art and fashion bringing together the talents of Australian and international writers and artists in a unique collaboration of styles and subjects.

The mu catchphrase is "Lollipop Culture for the Accelerated Generation," and is printed on matte recycled paper for "tomorrow's people today."

Also the mantra of Compassion, to be chanted while kneeling at the Shrine of Compassion, in Ultima IV, Quest of the Avatar.

See the nodes on Ultima for more info.

Also see http://www.tk421.net/ultima/u4.pdf for a quick rundown of the shrine locations, mantras, dungeon locations and other quite useful information.