- Source: Latin letters used in mathematics, science, and engineering
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:
Intensive quantities in physics are usually denoted with minusculeswhile extensive are denoted with capital letters.
Most symbols are written in italics.
Vectors can be denoted in boldface.
Sets of numbers are typically bold or blackboard bold.
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 Ar
work in classical mechanics
the pre-exponential factor in the Arrhenius Equation
electron affinity
A
{\displaystyle \mathbb {A} }
represents the algebraic numbers or affine space in algebraic geometry.
A blood type
A spectral type
a represents:
the first side of a triangle (opposite point A)
the scale factor of the expanding universe in cosmology
the acceleration in mechanics equations
the first constant in a linear equation
a constant in a polynomial
the unit are for area (100 m2)
the unit prefix atto (10−18)
the first term in a sequence or series
Reflectance
Bb
B represents:
the digit "11" in hexadecimal and other positional numeral systems with a radix of 12 or greater
the second point of a triangle
a ball (also denoted by ℬ (
B
{\displaystyle {\mathcal {B}}}
) or
B
{\displaystyle \mathbb {B} }
)
a basis of a vector space or of a filter (both also denoted by ℬ (
B
{\displaystyle {\mathcal {B}}}
))
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
B
{\displaystyle {\textbf {B}}}
or
B
→
{\displaystyle {\vec {B}}}
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
the molality of a solution
Bottom quark
Barn (10−24 cm2)
Cc
C represents:
the third point of a triangle
the digit "12" in hexadecimal and other positional numeral systems with a radix of 13 or greater
the unit coulomb of electrical charge
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
the circumference of a circle or other closed curve
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*
Carbon
Heat capacity
The C programming language
Cunningham correction factor
C
{\displaystyle \mathbb {C} }
represents the set of complex numbers.
A vertically elongated C with an integer subscript n sometimes denotes the n-th coefficient of a formal power series.
c represents:
the unit prefix centi (10−2)
the amount concentration in chemistry
the speed of light in vacuum
the third side of a triangle (opposite corner C)
Lowercase Fraktur
c
{\displaystyle {\mathfrak {c}}}
denotes the cardinality of the set of real numbers (the "continuum"), or, equivalently, of the power set of natural numbers.
the third constant in a linear equation
a constant in a polynomial
Charm quark
Speed of sound
Specific heat capacity
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 [distance2/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
Dimension
Deuterium
Electric displacement
D meson
Density
d represents
the differential operator
the unit day of time (86,400 s)
the difference in an arithmetic sequence
a metric operator/function
the diameter of a circle
the unit prefix deci (10−1)
a thickness
a distance
Down quark
Infinitesimal increment in calculus
Density
Ee
E represents:
the digit "14" in hexadecimal and other positional numeral systems with a radix of 15 or greater
an exponent in decimal numbers. For example, 1.2E3 is 1.2×103 or 1200
the set of edges in a graph or matroid
the unit prefix exa (1018)
energy in physics
electric field denoted
E
{\displaystyle {\textbf {E}}}
or
E
→
{\displaystyle {\vec {E}}}
electromotive force (denoted
E
{\displaystyle {\mathcal {E}}}
and measured in volts), refers to voltage
an event (as in P(E), which reads "the probability P of event E occurring")
in statistics, the expected value of a random variable, sometimes as
E
{\displaystyle \mathbb {E} }
Ek represents kinetic energy
(Arrhenius) activation energy, denoted Ea or EA
ionization energy, denoted Ei
electron affinity, denoted Eea
dissociation energy, denoted Ed
e represents:
Euler's number, a transcendental number equal to 2.71828182845... which is used as the base for natural logarithms
a vector of unit length, especially in the direction of one of the coordinates axes
the elementary charge in physics
an electron, usually denoted e− to distinguish against a positron e+
the eccentricity of a conic section
the identity element in a group
In a cartesian coordinate system, a unit vector in notations like
(
e
^
x
,
e
^
y
,
e
^
z
)
{\displaystyle (\mathbf {\hat {e}} _{x},\mathbf {\hat {e}} _{y},\mathbf {\hat {e}} _{z})}
, or
(
e
^
1
,
e
^
2
,
e
^
3
)
{\displaystyle (\mathbf {\hat {e}} _{1},\mathbf {\hat {e}} _{2},\mathbf {\hat {e}} _{3})}
Ff
F represents
the digit "15" in hexadecimal and other positional numeral systems with a radix of 16 or greater
the unit farad of electrical capacity
the Helmholtz free energy of a closed thermodynamic system of constant pressure and temperature
together with a degree symbol (°) represents the Fahrenheit measurement of temperature = °F
Fluorine
A spectral type
F represents
force in mechanics equations
pFq is a hypergeometric series
the probability distribution function in statistics
a Fibonacci number
an arbitrary functor
a field
an event space sigma algebra as part of a probability space, often as
F
{\displaystyle {\mathcal {F}}}
f represents:
the unit prefix femto (10−15)
f represents:
the generic designation of a function
Friction
Gg
G represents
an arbitrary graph, as in: G(V,E)
an arbitrary group
the unit prefix giga (109)
the Newtonian constant of gravitation
the Einstein tensor
the Gibbs energy
the centroid of a triangle
Catalan's constant
weight measured in newtons
Green's function
a spectral type
g represents:
the generic designation of a second function
the acceleration due to gravity on Earth
a unit of mass, the gramme
Gravitational field, denoted g
Metric tensor (general relativity)
Gluon
Hh
H represents:
an arbitrary subgraph
an arbitrary subgroup
a Hilbert space
the unit henry of magnetic inductance
the homology and cohomology functor
the enthalpy
the (Shannon) entropy of information
the orthocenter of a triangle
a partial sum of the harmonic series
Auxiliary magnetic field, denoted
H
{\displaystyle {\boldsymbol {H}}}
Hamiltonian in quantum mechanics
Hankel function
Heaviside step function
Higgs boson
Hydrogen
Set of quaternions
Hat matrix
H0 is either the Hubble constant; or the Dimensionless Hubble parameter of (100 h km·s−1·Mpc−1, with h being the associated error.
H
{\displaystyle \mathbb {H} }
represents the quaternions (after William Rowan Hamilton).
ΔH‡ represents the standard enthalpy of activation in the Eyring equation.
ℋ (
H
{\displaystyle {\mathcal {H}}}
) 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)× 10−34 J·s)
the unit prefix hecto (102)
the generic designation of a third function
the altitude of a triangle
a height
Spherical Hankel function
Ii
I represents:
the closed unit interval, which contains all real numbers from 0 to 1, inclusive
the identity matrix
the Irradiance
the moment of inertia
intensity in physics, typically the vector field I
Luminous intensity, typically Iv
the incenter of a triangle
the electric current
ionization energy, denoted I
I represents:
the index of an indexed family
Iodine
i represents:
the imaginary unit, a complex number that is the square root of −1
Imaginary quaternion unit
a subscript to denote the ith term (that is, a general term or index) in a sequence or list
the index to the elements of a vector, written as a subscript after the vector name
the index to the rows of a matrix, written as the first subscript after the matrix name
an index of summation using the sigma notation
the unit vector in Cartesian coordinates going in the x-direction, usually bold i
Jj
J represents:
the unit joule of energy
the current density in electromagnetism denoted
J
{\displaystyle {\boldsymbol {J}}}
the radiosity in thermal mechanics
the moment of inertia
Total angular momentum quantum number
Bessel function of the first kind
Impulse
J represents:
the scheme of a diagram in category theory
j represents:
the index to the columns of a matrix, written as the second subscript after the matrix name
in electrical engineering, the square root of −1, instead of i
in electrical engineering, the principal cube root of 1:
−
1
2
+
1
2
i
3
{\displaystyle -{\frac {1}{2}}+{\frac {1}{2}}i{\sqrt {3}}}
the unit vector in Cartesian coordinates going in the y-direction, usually bold j
Electrical current density
Spherical Bessel function of the first kind
Imaginary unit in electrical engineering (where i represents current)
Unit vector for the second imaginary dimension in the quaternion number system (bold j)
Kk
K represents:
the temperature unit kelvin
the functors of K-theory
an unspecified (real) constant
a field in algebra
with a subscript, a complete graph on that many vertices
the area of a polygon
kinetic energy
Kaon
Potassium
Sectional curvature
A spectral type
k represents
the unit prefix kilo- (103)
the Boltzmann constant, often represented as kB to avoid confusion
the angular wavenumber of the wave equation, the magnitude of the wave vector k
an integer, e.g. a dummy variable in summations, or an index of a matrix
an unspecified (real) constant
the spring constant of Hooke's law
the spacetime curvature from the Friedmann equations in cosmology
the rate constant (coefficient)
the unit vector in Cartesian coordinates going in the z-direction, usually bold k
Unit vector for the third dimension in the quaternion number system (bold k)
Unit vector in the z direction
Ll
L represents:
length, used often in quantum mechanics as the size of an infinite square well
angular momentum
the unit of volume the litre
the radiance
the space of all integrable real (or complex) functions
the space of linear maps, as in L(E,F) or L(E) = End(E)
the likelihood function
a formal language
the operator creating a line graph
the lag operator in statistics
a Lucas number
the Lagrange function
Inductance in electromagnetism (measured in henries)
A spectral type
l represents:
the unit of volume the litre (often avoided due to confusion with the number 1 and uppercase letter I)
the length of a side of a rectangle or a cuboid (e.g. V = lwh; A = lw)
the last term of a sequence or series (e.g. Sn = n(a+l)/2)
the orbital angular momentum quantum number
ℒ (
L
{\displaystyle {\mathcal {L}}}
) 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- (106)
the Madelung constant for crystal structures held by ionic bonding
the moment of force
Torque when denoted as moment of force
molar mass
molar mass constant, denoted Mu
relative molecular mass, denoted Mr
Magnetization vector field M
A spectral type
m represents:
the number of rows in a matrix
atomic mass
atomic mass constant denoted mu
the slope in a linear regression or in any line
the mass in mechanics equations
the unit metre of length
the unit prefix milli (10−3)
a median of a triangle
the overall order of reaction
Magnitude
Minute (but the SI abbreviation is "min")
Slope
Magnetic moment in a magnetization field
Nn
N represents
the unit newton of force
the nine-point center of a triangle
Bessel function of the second kind (uncommon)
Nitrogen
Normal distribution
Normal vector
N represents
the neutron number
The number of particles of a thermodynamical system: 57
NA represents the Avogadro constant
N
{\displaystyle \mathbb {N} }
represents the natural numbers.
n represents
A neutron, which may be shown as n, n0 or 10n
the unit prefix nano (10−9)
n represents
the number of columns in a matrix
the "number of" in algebraic equations
the number density of particles in a volume
the index of the nth term of a sequence or series (e.g. tn = a + (n − 1)d)
the principal quantum number
the amount of a given substance
the number concentration
the overall order of reaction
Refractive index of a material
Spherical Bessel function of the second kind (uncommon)
An integer
Oo
O represents
the order of asymptotic behavior of a function (upper bound); see Big O notation
(
0
,
0
,
…
,
0
)
{\displaystyle (0,0,\ldots ,0)}
— 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
O
{\displaystyle \mathbb {O} }
represents
the octonions
Pp
P represents:
the pressure in physics equations: 4
the unit prefix peta (1015)
probability in statistics and statistical mechanics: 35
an arbitrary point in geometry
with a subscript, a path on that many vertices
power, measured in watts
Active power in electrical engineering
weight measured in newtons
Legendre polynomial
Phosphorus
Polarization
P
{\displaystyle \mathbb {P} }
represents
the prime numbers
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 (10−12)
a proton, often p+ or 11 p
the linear momentum in physics equations
the perimeter of a triangle or other polygon
generalized momentum
the pressure in physics equations
Sound pressure
Electric dipole moment
Q represents:
heat energy: 6
electroweak charge, denoted QW
Reactive power in electrical engineering
Volumetric flow rate
Q
{\displaystyle \mathbb {Q} }
represents the rational numbers
q represents:
a second prime number
the denominator of a fraction
the quotient resulting from integer division
the deceleration parameter in cosmology
electric charge of a particle
a generalized coordinate
Quark
Rr
R represents:
the Ricci tensor
the circumradius of a cyclic polygon such as a triangle
an arbitrary relation
Riemann curvature tensor
Electrical resistance
Molar gas constant
R
{\displaystyle \mathbb {R} }
represents the set of real numbers and various algebraic structures built upon the set of real numbers, such as
R
n
{\displaystyle \mathbb {R} ^{n}}
.
r represents:
the radius of a circle or sphere
radial distance in a polar coordinate system or spherical coordinate system
the inradius of a triangle or other tangential polygon
the ratio of a geometric series (e.g. arn−1)
the remainder resulting from integer division
the separation of two objects, for example in Coulomb's law
a position vector
the rate of concentration change of B (due to chemical reaction) denoted rB
Ss
S represents
a sum
the unit siemens of electric conductance
the unit sphere (with superscript denoting dimension)
the scattering matrix
entropy
action in joule-seconds
Apparent power in electrical engineering
Area
Spin operator
Sulfur
Symmetric group
with a subscript, a symmetric group on that many objects
s represents:
an arclength
a path length
the displacement in mechanics equations
the unit second of time
a complex variable s = σ + i t in analytic number theory
the semiperimeter of a triangle or other polygon
Strange quark
Specific entropy
𝒮 (
S
{\displaystyle {\mathcal {S}}}
) represents a system's action in physics
S
{\displaystyle \mathbb {S} }
represents
the sedenions
Tt
T represents:
the top element of a lattice
a tree (a special kind of graph)
temperature in physics equations: 4
the unit tesla of magnetic flux density
the unit prefix tera (1012)
the stress–energy tensor
tension in physics
an arbitrary monad
the time it takes for one oscillation
kinetic energy
Torque
A spectral type
Tritium
Period, the reciprocal of frequency
t represents:
time in graphs, functions or equations
a term in a sequence or series (e.g. tn = tn−1 + 5)
the imaginary part of the complex variable s = σ + it in analytic number theory
the sample statistic resulting from a Student's t-test
the half life of a quantity, denoted as t1⁄2
Top quark
T
{\displaystyle \mathbb {T} }
represents
the trigintaduonions
Uu
U represents:
a U-set which is a set of uniqueness
a unitary operator
in thermodynamics, the internal energy of a system
a forgetful functor
Potential energy
Uranium
U(n) represents the unitary group of degree n
∪ represents the union operator
u represents:
the initial velocity in mechanics equations
Up quark
Vv
V represents:
Vanadium
the unit volt of voltage
the set of vertices in a graph
a vector space
potential energy
molar volume denoted by Vm
v represents
the final velocity in mechanics equations
frequency, especially when referring to electromagnetic waves
a specific volume in classical mechanics
the rate of concentration change of B (due to chemical reaction) denoted vB
the rate of reaction based on amount concentration denoted v or vc
the rate of reaction based on number concentration denoted v or vC
Ww
W represents:
the unit watt of power
work, both mechanical and thermodynamical: 8–9
in thermodynamics, the number of possible quantum states in Boltzmann's entropy formula
weight measured in newtons
Lambert's W function
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
x represents
a realized value of a random variable
an unknown variable, most often (but not always) from the set of real numbers, while a complex unknown would rather be called z, and an integer by a letter like m from the middle of the alphabet
the coordinate on the first or horizontal axis in a Cartesian coordinate system, or the viewport in a graph or window in computer graphics; the abscissa
Axis in the direction of travel of an aerospace vehicle (longitudinal axis)
a mole fraction
Variable to be determined in an algebraic equation
A vector in linear algebra
Yy
Y represents:
the unit prefix yotta- (1024)
Bessel function of the second kind
the second part of a bipartite graph
Yttrium
Gross domestic product
Y represents:
a second random variable
y represents:
the unit prefix yocto- (10−24)
a realized value of a second random variable
a second unknown variable
the coordinate on the second or vertical axis (backward axis in three dimensions) in a Cartesian coordinate system, or in the viewport of a graph or window in computer graphics; the ordinate
The port-starboard axis (transverse axis) of an aerospace vehicle
a mole fraction
Zz
Z represents:
the unit prefix zetta (1021)
the atomic number or proton number of an element in chemistry
a standardized normal random variable in probability theory and statistics
Partition function
in meteorology, the radar reflectivity factor
Electrical impedance
Z boson
Compressibility factor
Z
{\displaystyle \mathbb {Z} }
represents the integers
z represents:
the unit prefix zepto (10−21)
the coordinate on the third or vertical axis in three dimensional space
The vertical axis or altitude in an aerospace vehicle
the view depth in computer graphics, see also "z-buffering"
the argument of a complex function, or any other variable used to represent a complex value
in astronomy, wavelength redshift: 9
a third unknown variable
the collision frequency of A with A is denoted zA(A)
the collision frequency factor is denoted zAB
See also
Blackboard bold letters used in mathematics
Greek letters used in mathematics, science, and engineering
List of letters used in mathematics, science, and engineering
Mathematical Alphanumeric Symbols
Glossary of mathematical symbols
References
Kata Kunci Pencarian:
- Laju cahaya
- Perancangan cerdas
- Latin letters used in mathematics, science, and engineering
- Greek letters used in mathematics, science, and engineering
- List of letters used in mathematics, science, and engineering
- List of common physics notations
- Glossary of mathematical symbols
- Blackboard bold
- Mathematical Alphanumeric Symbols
- Mathematical notation
- Mathematical operators and symbols in Unicode
- Delta (letter)
