List of letters used in mathematics and science

• Intensive quantities[?] in physics are usually denoted with minuscules, while extensive[?] are denoted with capital letters.
• Vectors are bold[?].
• Sets of numbers are blackboard bold.

Å - Ångström

A - Blood Antigen[?], Magnetic vector potential[?], Work,

B - B meson[?], Blood Antigen[?], Boron, Luminance, Magnetic field,

C - Coulomb, Degrees Celsius, Carbon, Set of complex numbers, Specific heat capacity, Molar heat capacity[?] (C_p),

D - Electric displacement[?],

E - Electric field, Energy, SI prefix: (exa-), Expected value,

F - Farad, degrees Fahrenheit, Fluorine, Force, Helmholtz free energy[?],

G - Einstein tensor[?], SI prefix: (giga-), Gibbs free energy[?], Gravitational constant, Green's function[?], Momentum,

H - Auxiliary magnetic field[?], Enthalpy, Hamiltonian, Hankel function[?], Heaviside step function, Henry, Hydrogen,

I - Current, Iodine, Impulse, Luminous intensity[?], Moment of inertia,

J - Angular momentum, Bessel function of the first kind, Current, Joule,

K - Kaon[?], degrees Kelvin, Potassium,

L - Angular momentum, Inductance, Lagrangian,

M - Magnetization[?], Mass, SI prefix: (mega-), Torque,

N - Avogadro's number (N_A), Set of natural numbers, Newton, Bessel function of the second kind, Nitrogen, Normal distribution,

O - a Blood antigen[?], Big O notation, Ohm, Oxygen,

P - Legendre polynomial, Luminous flux[?], Phosphorus, Polarization, Power, Pressure, Probability,

Q - Electric charge, (Quantity of) heat, Set of rational numbers,

R - Electrical resistance, Radius, Set of real numbers,

S - Area, Entropy, Sphere, Spin operator, Sulfur, Symmetric group,

T - Temperature, Tesla,

U - Potential energy, Uranium, Unitary operator,

V - Potential energy, Volt, Volume,

W - Energy, Lambert's W function, Watt, Work, Work function,

X - Random variable,

Y - Bessel function of the second kind, SI prefix: (yotta-), Yttrium,

Z - SI prefix: (zetta-), Atomic number, Impedance, Set of integers, Partition function,

a - SI prefix: (atto-), Acceleration, Reflectance,

b - Bottom quark

c - SI prefix: (centi-), Charm quark, Speed of light, Speed of sound,

d - SI prefix: (deci-), Distance, Down quark, Infinitesimal quantity,

e - Napier's constant, Electron, Electric charge,

f - SI prefix: (femto-), Frequency,

g - gram, Gravitational acceleration, Gravitational field, Distance metric of spacetime,

h - Height, Hour, Planck's constant, Spherical Hankel function[?],

i - Imaginary unit, Unit vector,

j - Current and current density, Imaginary unit, Radiant intensity[?], Spherical Bessel function[?] of the first kind, Unit vector,

k - Boltzmann constant (k_B), SI prefix: (kilo-), Wave vector[?], Unit vector,

l - Length, Litre, Mean free path,

m - Magnitude, Mass, SI prefix: (milli-), Meter, Minute,

n - Amount of substance[?], SI prefix: (nano-), Neutron, Refractive index, Spherical Bessel function[?] of the second kind,

o -

p - Electric dipole moment[?], Momentum, SI prefix: (pico-), Proton,

q - Electric charge, Generalized coordinate,

r - Position (vector)[?], Radial polar coordinate, Radius,

s - Second, Strange quark,

t - Period, Time, Top quark,

u - Up quark,

v - Velocity,

w - Velocity,

x - Position[?] coordinate,

y - Position[?] coordinate, SI prefix: (yocto-),

z - Complex number, Position[?] coordinate, SI prefix: (zepto-),

Γ - Angular momentum, Gamma function,

Δ -

Θ - Heaviside step function,

Λ - Iwasava algebra[?], Lorentz transformation,

Ξ -

Π - Product,

Σ - Sum,

Φ -

Ψ - Quantum mechanical wavefunction,

Ω - Chaitin's constant, Ohm, Solid angle,

α - Alpha particle, Fine structure constant,

β - Inverse temperature[?],

γ - Euler-Mascheroni constant, Gamma-ray (Photon), Photon, Relativistic gamma factor[?],

δ - Dirac delta function, Infinitesimal quantity, Kronecker delta,

ε - Infinitesimal quantity, Permittivity,

ζ - Riemann zeta function,

η - Distance metric of flat spacetime, Efficiency[?], Dynamic viscosity,

θ - Angle, Angular polar coordinate, Temperature,

ι -

κ - Gravitational constant,

λ - Half life, Lagrangian multiplicator[?], Lambda expression, Thermal conductivity, Wavelength,

μ - Absorption coefficient, Chemical potential, Magnetic moment[?], Mean, SI prefix: (micro-), Muon, Permeability, Reduced mass,

ν - Frequency, Kinematic viscosity[?], Neutrino,

ξ -

ο -

π - Conjugate momentum, Number π, Pion,

ρ - Density, Electrical resistivity, Radial polar coordinate,

σ - Cross section, Electrical conductivity, Spin, Standard deviation, Stefan-Boltzmann constant,

τ - Tau lepton[?], Torque,

υ -

φ - Angular polar coordinate, Electric scalar potential[?], Euler's totient function, Golden mean, Phase, Potential energy,

χ - Electric susceptibility[?],

ψ - Quantum mechanical wavefunction,

ω - Frequency,

Ш - Shafarevich-Tate group[?] (Ш(G)),

א - Cardinality of infinite sets