Mathematics

Metric ton The metric ton (t) is a mass unit equal to 1,000 kilograms or one megagram, widely used in countries adopting the International System of Units for trade, science, and industry.

Micrometre (micron): the SI unit for small lengths Micrometre The micrometre (µm), also called the micron and spelled micrometer in American English, equals one millionth of a metre and is used for wavelengths, cells, particles and precision…

Microsecond (μs): the unit of time equal to one millionth of a second Microsecond A microsecond (μs) is 10⁻⁶ second — 1,000 nanoseconds or 1/1,000 of a millisecond. Used widely in electronics, physics, and computing where millionth-of-a-second precision matters.

Mile (unit of length) Mile A mile is a unit of length historically rooted in the Roman mille passus. The international (statute) mile equals 1,609.344 metres; several regional and historical variants—such as…

Millennium Prize Problems Seven famous mathematical problems designated by the Clay Mathematics Institute in 2000, each carrying a $1,000,000 prize; only one has been effectively resolved so far.

Millimetre (mm): metric unit of length Millimetre The millimetre (mm) is a SI-derived unit equal to one thousandth of a metre, widely used for measuring small lengths in engineering, manufacturing, science and everyday life.

Million: the number 1,000,000 — definition, uses, history and cultural role Million One million (1,000,000) is the integer between 999,999 and 1,000,001. This article explains its mathematical meaning, notation, origin, measurement uses, idioms, and notable distin…

Millisecond: unit of time and its significance Millisecond A millisecond (ms) is one thousandth of a second. This article explains the unit, common conversions, everyday and scientific examples, perceptual thresholds, and its role in techn…

Min — meanings, names, and common uses Min Concise guide to the word 'Min': its use as a name and title (Egyptian deity, Chinese and Korean names), as a regional and linguistic label (Min Chinese), and as common abbreviatio…

Minimum spanning tree A concise, neutral overview of minimum spanning trees in weighted graphs: definition, key properties, common algorithms, history, applications and notable distinctions.

Minute (time unit and angular measure) Minute A minute commonly refers to 60 seconds of time or to 1/60 of a degree of arc (an arcminute). This article explains the meanings, history, notation, and principal uses of the minute…

Miranda — an early pure functional programming language Miranda (programming language) Miranda is a non-strict, purely functional language from the 1980s that influenced later languages (notably Haskell). It provided lazy evaluation, algebraic datatypes, polymorphic…

Möbius strip (Möbius band) Möbius strip A Möbius strip is a simple non‑orientable surface with only one side and one boundary component, created by giving a strip a half‑twist before joining its ends. It is a fundamental…

Mode: meanings in statistics, music, language, and technology Mode Overview of the term 'mode' across disciplines: statistical mode, musical modes, grammatical senses, technological and physical modes, their origins, distinctions, and common uses.

Mode (statistics) The mode is the value(s) that appear most frequently in a dataset or the peak(s) of a probability distribution; used to describe typical values, especially for categorical or skewe…

Modular arithmetic (clock arithmetic) Modular arithmetic Modular arithmetic studies integers with wrap‑around at a fixed modulus; operations like addition, subtraction and multiplication are performed modulo n. Used in number theory, cry…

Modular origami Form of paperfolding where many identical folded units are assembled into larger geometric and decorative structures; uses pocket-and-flap connections and often produces polyhedral…

Modularity theorem (Taniyama–Shimura–Weil) Modularity theorem The Modularity theorem asserts that every elliptic curve over the rational numbers is associated with a modular form. Its proof reshaped number theory and enabled the proof of Ferm…

Module (mathematics) A module is an algebraic structure like a vector space but defined over a ring. It generalizes abelian groups and underpins many constructions in algebra, geometry and representati…

Modulo operation (remainder and modular arithmetic) Modulo operation The modulo operation returns the remainder after integer division and underpins modular arithmetic. This article explains definition, notation, properties, computation, history, an…

Monad (mathematics, programming, and philosophy) Monad A monad is a structural concept in category theory and functional programming that models composition of computations; the word also names Leibniz's metaphysical simples in philoso…

Monoid (algebraic structure) Monoid A monoid is a set equipped with an associative binary operation that has an identity element. It is a fundamental concept in algebra and computer science with many concrete example…

Monomial: single-term expressions in algebra Monomial A monomial is an algebraic expression consisting of a single term: a product of a numeric coefficient and variables with nonnegative integer exponents. Definitions, examples, opera…

Monotonic function A monotonic function (monotone) is one that preserves order on an interval: it is either nondecreasing or nonincreasing. This article explains definitions, types, calculus relation…

Monster group (Fischer–Griess Monster) Monster group The Monster is the largest sporadic finite simple group, a highly symmetrical mathematical object linked to algebra, modular forms, and theoretical physics.

Monte Carlo algorithm A Monte Carlo algorithm uses randomness and statistical sampling to estimate solutions for problems that are difficult or impossible to solve deterministically. Common in simulatio…

Monty Hall problem: probability puzzle, solution, and significance Monty Hall problem A probability puzzle originating from the TV show Let's Make a Deal. Explains the three-door setup, why switching doubles the win probability, historical controversy, and common va…

Mortality rate: definition, types, calculation and public health importance Mortality rate Mortality rate quantifies deaths in a population over time. This article explains definitions, common measures, calculation, historical use, public-health applications, and limitat…

Most common words in English — frequency, methods, and uses Most common words in English Overview of how frequency lists are made, what 'most common words' means (lemmas vs forms), historical sources, notable patterns, and practical uses in teaching and technology.

Mu: meanings, symbols, and cultural uses of μ / Μ Mu Overview of Mu (Μ, μ): the Greek letter, its roles as SI prefix and scientific symbol, mathematical uses, linguistic and cultural meanings, and notable names and distinctions.

Mu (Greek letter) Mu (letter) Mu (Μ, μ) is the twelfth letter of the Greek alphabet, representing the /m/ sound, with a numeric value of 40. It is widely used as a symbol in mathematics, science, engineering an…

Mu (unit of area) Mu is a traditional East Asian unit of land area, now standardized in China as 1/15 hectare (≈666.67 m²). It remains in common use for agricultural and local land measures.

Multibrot set A family of fractal parameter sets in the complex plane defined by iterating z ↦ z^d + c. Generalizes the Mandelbrot set; important in complex dynamics, fractal visualization and t…

Multiplication: the arithmetic operation and its mathematical role Multiplication Multiplication is an arithmetic operation that produces a product by combining quantities. This article explains its meanings, properties, history, algorithms, and distinctions acr…

Multiplication table: definition, structure, history and educational uses Multiplication table An overview of the multiplication table: what it is, common layouts and patterns, historical origins, uses in teaching and arithmetic, and notable properties such as symmetry and s…

Multiset (Bag): Definition, Properties and Applications Multiset A multiset (or bag) generalizes the set by allowing repeated elements. This article explains definitions, notation, operations, counting formulas, history, examples and common dist…

Multivariable calculus Study of calculus in two or more variables: partial derivatives, gradients, multiple integrals, vector operators and applications in geometry, physics and engineering.

Mutual information Mutual information quantifies how much knowing one random variable reduces uncertainty about another. It is a symmetric, nonnegative measure used across statistics, communications,…

N — the fourteenth letter of the Latin alphabet N N is the fourteenth letter of the modern Latin alphabet. It represents an alveolar nasal consonant, has distinct uppercase/lowercase forms, and appears widely in language, science,…

Nth root: definition, notation, properties, and uses n th root An nth root of a number is a value which raised to the power n gives the number. This article explains notation, real and complex roots, properties, history, examples, and common c…

Names for ordinal numbers in English Names for ordinal numbers An overview of English ordinal numbers: formation rules, spelling changes, numeric suffixes (1st, 2nd), hyphenation, common exceptions and examples for compound numbers and hundred…

Names of Large Numbers: Notation, Scales, and Uses Names of large numbers Overview of how very large numbers are named and written, including scientific notation, grouping names, short and long scales, SI prefixes, examples and practical conventions.

Naming and notation for very small numbers Names of small numbers How very small numbers are expressed: decimal place names, scientific notation, SI prefixes, reading examples, and practical distinctions for measurement and computation.

Nanosecond A nanosecond (ns) is one billionth of a second (10⁻⁹ s). This article explains the unit, common comparisons, physical examples, technological relevance and historical notes.

Natural deduction: a system for formal reasoning Natural deduction Natural deduction is a family of formal proof systems designed to mirror everyday logical reasoning. It emphasizes introduction and elimination rules, subproofs, and close ties to…

Natural number Natural numbers are the basic counting numbers (nonnegative integers used for counting and ordering); conventions vary about whether zero is included.

Nearest neighbour algorithm Overview of nearest neighbour methods: the greedy TSP heuristic and the k‑nearest neighbour approach used for classification and search, with characteristics, limits, and practical…

Nearest-neighbor interpolation (point sampling) Nearest-neighbor interpolation A simple interpolation method that assigns to each query location the value of the closest sampled point; common in image scaling, GIS and categorical resampling.