Many letters of the Latin alphabet, both capital and small, are used in mathematics, science, and engineering to denote by convention specific or abstracted constants, variables of a certain type, units, multipliers, or physical entities. Certain letters, when combined with special formatting, take on special meaning.

Below is an alphabetical list of the letters of the alphabet with some of their uses. The field in which the convention applies is mathematics unless otherwise noted.

Typographical variation

Some common conventions:

  • Most symbols are written in italics.
  • Vectors can be denoted in boldface.
  • Sets of numbers are typically bold or blackboard bold.

{| class="wikitable"

|+ Typographical variations of Latin letters in Unicode

|-

! Name

! Sub-type

! Alphabet

|-

| rowspan=3 style="text-align: center;" | Double-struck

| rowspan=2 style="text-align: center;" | Mathematical

|

|-

|

|-

| style="text-align: center;" | Italic

| ⅆ ⅇ ⅈ ⅉ ⅅ

|-

| rowspan=4 style="text-align: center;" | Script/Calligraphy

| rowspan=2 style="text-align: center;" | Mathematical

| 𝒜 ℬ 𝒞 𝒟 ℰ ℱ 𝒢 ℋ ℐ 𝒥 𝒦 ℒ ℳ 𝒩 𝒪 𝒫 𝒬 ℛ 𝒮 𝒯 𝒰 𝒱 𝒲 𝒳 𝒴 𝒵

|-

| 𝒶 𝒷 𝒸 𝒹 ℯ 𝒻 ℊ 𝒽 𝒾 𝒿 𝓀 𝓁 𝓂 𝓃 ℴ 𝓅 𝓆 𝓇 𝓈 𝓉 𝓊 𝓋 𝓌 𝓍 𝓎 𝓏

|-

| rowspan=2 style="text-align: center;" | Mathematical Bold

| 𝓐 𝓑 𝓒 𝓓 𝓔 𝓕 𝓖 𝓗 𝓘 𝓙 𝓚 𝓛 𝓜 𝓝 𝓞 𝓟 𝓠 𝓡 𝓢 𝓣 𝓤 𝓥 𝓦 𝓧 𝓨 𝓩

|-

| 𝓪 𝓫 𝓬 𝓭 𝓮 𝓯 𝓰 𝓱 𝓲 𝓳 𝓴 𝓵 𝓶 𝓷 𝓸 𝓹 𝓺 𝓻 𝓼 𝓽 𝓾 𝓿 𝔀 𝔁 𝔂 𝔃

|-

| rowspan=4 style="text-align: center;" | Fraktur

| rowspan=2 style="text-align: center;" | Mathematical

| 𝔄 𝔅 ℭ 𝔇 𝔈 𝔉 𝔊 ℌ ℑ 𝔍 𝔎 𝔏 𝔐 𝔑 𝔒 𝔓 𝔔 ℜ 𝔖 𝔗 𝔘 𝔙 𝔚 𝔛 𝔜 ℨ

|-

| 𝔞 𝔟 𝔠 𝔡 𝔢 𝔣 𝔤 𝔥 𝔦 𝔧 𝔨 𝔩 𝔪 𝔫 𝔬 𝔭 𝔮 𝔯 𝔰 𝔱 𝔲 𝔳 𝔴 𝔵 𝔶 𝔷

|-

| rowspan=2 style="text-align: center;" | Mathematical Bold

| 𝕬 𝕭 𝕮 𝕯 𝕰 𝕱 𝕲 𝕳 𝕴 𝕵 𝕶 𝕷 𝕸 𝕹 𝕺 𝕻 𝕼 𝕽 𝕾 𝕿 𝖀 𝖁 𝖂 𝖃 𝖄 𝖅

|-

| 𝖆 𝖇 𝖈 𝖉 𝖊 𝖋 𝖌 𝖍 𝖎 𝖏 𝖐 𝖑 𝖒 𝖓 𝖔 𝖕 𝖖 𝖗 𝖘 𝖙 𝖚 𝖛 𝖜 𝖝 𝖞 𝖟

|-

| rowspan=2 style="text-align: center;" | Mono-space

| rowspan=2 style="text-align: center;" | Mathematical

| 𝙰 𝙱 𝙲 𝙳 𝙴 𝙵 𝙶 𝙷 𝙸 𝙹 𝙺 𝙻 𝙼 𝙽 𝙾 𝙿 𝚀 𝚁 𝚂 𝚃 𝚄 𝚅 𝚆 𝚇 𝚈 𝚉

|-

| 𝚊 𝚋 𝚌 𝚍 𝚎 𝚏 𝚐 𝚑 𝚒 𝚓 𝚔 𝚕 𝚖 𝚗 𝚘 𝚙 𝚚 𝚛 𝚜 𝚝 𝚞 𝚟 𝚠 𝚡 𝚢 𝚣

|}

Aa

  • A represents:
  • the first point of a triangle
  • the digit "ten" in hexadecimal and other positional numeral systems with a radix of 11 or greater
  • the unit ampere for electric current in physics
  • the area of a figure
  • the mass number or nucleon number of an element in chemistry
  • the Helmholtz free energy of a closed thermodynamic system of constant pressure and temperature
  • a vector potential, in electromagnetics it can refer to the magnetic vector potential
  • with a subscript, an alternating group on that many objects
  • an Abelian group in abstract algebra
  • the Glaisher–Kinkelin constant
  • atomic weight, denoted by A<sub>r</sub>
  • electron affinity
  • <math>\mathbb{A}</math> represents the algebraic numbers or affine space in algebraic geometry.
  • A spectral type
  • a represents:
  • the first side of a triangle (opposite point A)
  • the acceleration in mechanics equations
  • the unit prefix atto (10<sup>−18</sup>)
  • the first term in a sequence or series
  • Reflectance

Bb

  • B represents:
  • the digit "11" in hexadecimal
  • a basis of a vector space or of a filter (both also denoted by ℬ (<math>\mathcal{B}</math>))
  • in econometrics and time-series statistics it is often used for the backshift or lag operator, the formal parameter of the lag polynomial
  • the magnetic field, denoted <math>\textbf{B}</math> or <math>\vec{B}</math>
  • B with various subscripts represents several variations of Brun's constant and Betti numbers; it can also be used to mean the Bernoulli numbers.
  • B meson
  • A blood type
  • Boron
  • Buoyancy
  • Bulk modulus
  • Luminance
  • A spectral type
  • b represents:
  • the second side of a triangle (opposite point B)
  • the impact parameter in nuclear scattering
  • the second constant in a linear equation
  • usually with an index, sometimes with an arrow over it, a basis vector
  • a breadth
  • capacitance in electrical theory
  • with indices denoting the number of combinations, a binomial coefficient
  • together with a degree symbol (°), the Celsius measurement of temperature = °C
  • with a subscript, a cycle on that many vertices
  • with a subscript, a cyclic group of that order
  • the complement of a set (lowercase c and the symbol ∁ are also used)
  • an arbitrary category
  • the number concentration
  • the third side of a triangle (opposite corner C)
  • the third constant in a linear equation
  • a constant in a polynomial
  • Charm quark
  • Speed of sound
  • Specific heat capacity
  • Lowercase Fraktur <math>\mathfrak{c}</math> denotes the cardinality of the set of real numbers (the "continuum"), or, equivalently, of the power set of natural numbers.

Dd

  • D represents
  • the digit "13" in hexadecimal and other positional numeral systems with a radix of 14 or greater
  • diffusion coefficient or diffusivity in dimensions of [distance<sup>2</sup>/time]
  • the differential operator in Euler's calculus notation
  • with a subscript, a dihedral group of that order or a dihedral group on a regular polygon of that many sides, depending on the convention chosen
  • dissociation energy
  • dissociation energy, denoted E<sub>d</sub>
  • ℋ (<math>\mathcal{H}</math>) represents the Hamiltonian in Hamiltonian mechanics.
  • h represents:
  • the class number in algebraic number theory
  • a small increment in the argument of a function
  • the unit hour for time (3600 s)
  • the Planck constant (6.626 069(57)× 10<sup>−34</sup> J·s)
  • the unit prefix hecto (10)
  • ℒ (<math>\mathcal{L}</math>) represents:
  • the Lagrangian (sometimes just L)
  • exposure (in particle physics)
  • ℓ represents:
  • Mean free path

Mm

  • M represents:
  • a manifold
  • a metric space
  • a matroid
  • the unit prefix mega- (10<sup>6</sup>)
  • N<sub>A</sub> represents the Avogadro constant
  • <math>\mathbb{N}</math> represents the natural numbers.
  • n represents
  • A neutron, which may be shown as , or n
  • the unit prefix nano (10<sup>−9</sup>)
  • <math>(0,0,\ldots,0)</math>&nbsp;— the Origin of the coordinate system in Cartesian coordinates
  • the circumcenter of a triangle or other cyclic polygon, or more generally the center of a circle
  • A blood type
  • Oxygen
  • A spectral type
  • o represents
  • the order of asymptotic behavior of a function (strict upper bound); see Little o notation (also known as "small o notation")
  • the order of an element in a group
  • <math>\mathbb{O}</math> represents
  • the octonions

Pp

  • P represents:
  • the pressure in physics equations
  • Projective space
  • Projection (linear algebra)
  • a probability (as in P(E), which reads "the probability P of event E happening")
  • p represents
  • a prime number
  • the numerator of a fraction
  • the unit prefix pico (10<sup>−12</sup>)
  • heat energy
  • q represents:
  • the unit prefix quecto- (10<sup>−30</sup>)

Ss

  • S represents
  • a sum
  • the unit siemens of electric conductance
  • Up quark

Vv

  • V represents:
  • Vanadium
  • the unit volt of voltage
  • a specific volume in classical mechanics
  • Tungsten
  • W boson
  • Work function
  • Wiener process
  • w represents:
  • the coordinate on the fourth axis in four-dimensional space
  • work in classical mechanics
  • Width

Xx

  • X represents
  • a random variable
  • a triangle center
  • the first part of a bipartite graph
  • Ẋ represents
  • the rate of change of quantity X
  • z represents:
  • the unit prefix zepto (10<sup>−21</sup>)
  • a third unknown variable
  • the collision frequency of A with A is denoted z<sub>A</sub>(A)
  • the collision frequency factor is denoted z<sub>AB</sub>