Mu (Μ, μ) Definition

The lowercase letter mu (μ) is used as a special symbol in many academic fields. Uppercase mu is not used, because it appears identical to Latin M.

The lowercase Mu (μ) is used for:

• Measurement:

• The SI prefix micro, which represents one millionth, or 10^-6. Lowercase letter u is often substituted for μ when the Greek character is not typographically available; for example the unit microfarad, correctly μF, is often rendered as uF or ufarad in technical documents.

• The micron μ, an old unit now named the micrometer and denoted μm.

• Mathematics:

• μ is conventionally used to denote certain things; however, any Greek letter or other symbol may be used freely as a variable name.

• A measure in measure theory.

• Minimalization in computability theory and Recursion theory.

• The integrating factor in ordinary differential equations.

• The learning rate in artificial neural networks.

• The degree of membership in a fuzzy set.

• The Möbius function in number theory.

• The population mean or expected value in probability and statistics.

• The Ramanujan–Soldner constant.

• Physics & Engineering:

• The coefficient of friction (also used in aviation as braking coefficient).

• Reduced mass in the two-body problem.

• Standard gravitational parameter in celestial mechanics.

• Linear density, or mass per unit length, in strings and other one-dimensional objects.

• Permeability in electromagnetism.

• The magnetic dipole moment of a current-carrying coil.

• Dynamic viscosity in fluid mechanics.

• The amplification factor or voltage gain of a triode vacuum tube.

• The electrical mobility of a charged particle.

• The rotor advance ratio, the ratio of aircraft airspeed to rotor tip speed in rotorcraft.

• Chemistry:

• The prefix given in IUPAC nomenclature for a bridging ligand.

• Biology:

• The mutation rate in population genetics.

• Pharmacology:

• An important opiate receptor.

• Orbital Mechanics:

• Standard gravitational parameter of a celestial body, the product of the gravitational constant G and the mass M.

• Planetary discriminant, represents an experimental measure of the actual degree of cleanliness of the orbital zone, a criterion for defining a planet. The value of µ is calculated by dividing the mass of the candidate body by the total mass of the other objects that share its orbital zone.

• Music:

• Mu major chord.

• Electronic musician Mike Paradinas runs the label Planet Mu which utilizes the letter as its logo, and releases music under the pseudonym μ-Ziq, pronounced music.

• Used as the name of the school idol group μ's, pronounced muse, consisting of nine singing idols in the anime Love Live! School Idol Project.

• Official fandom name of Kpop group f(x), appearing as either MeU or μ.

The letters of the Ancient Greek Alphabet, which are frequently utilized in math and science:

• Greek Alphabet
• Greek Numerals

“Mu (Letter).” Wikipedia, Wikimedia Foundation, 12 Apr. 2020, en.wikipedia.org/wiki/Mu_(letter).