List of common physics notations

This is a list of common physical constants and variables, and their notations. Note that bold text indicates that the quantity is a vector.

Latin characters

class="wikitable"
Symbol ! Meaning ! SI unit of measure
style="text-align: center" \| $\mathbf{A}$ \| magnetic vector potential \| tesla meter (T⋅m)
rowspan=3 style="text-align: center" \| $A$ \| area \| square meter (m²)
amplitude \| meter
atomic mass number \| unitless
style="text-align: center" \| $\mathbf{a}$ \| acceleration \| meter per second squared (m/s²)
style="text-align: center" \| $\mathbf{B}$ \| magnetic flux density also called the magnetic field density or magnetic induction \| tesla (T), or equivalently, weber per square meter (Wb/m²)
rowspan=3 style="text-align: center" \| $C$ \| capacitance \| farad (F)
heat capacity \| joule per kelvin (J⋅K⁻¹)
constant of integration \| varied depending on context
rowspan=4 style="text-align: center" \| $c$ \| speed of light (in vacuum) \| 299,792,458 meters per second (m/s)
speed of sound \| meter per second (m/s)
specific heat capacity \| joule per kilogram per kelvin (J⋅kg⁻¹⋅K⁻¹)
viscous damping coefficient \| kilogram per second (kg/s)
style="text-align: center" \| $\mathbf{D}$ \| electric displacement field also called the electric flux density \| coulomb per square meter (C/m²)
rowspan=2 style="text-align: center" \| $D$ \| density \| kilogram per cubic meter (kg/m³)
diameter \| meter (m)
rowspan=4 style="text-align: center" \| $d$ \| distance \| meter (m)
direction \| unitless
impact parameter \| meter (m)
differential (e.g. $dx$ ) \| varied depending on context
style="text-align: center" \| $d\mathbf{A}$ \| differential vector element of surface area A, with infinitesimally small magnitude and direction normal to surface S \| square meter (m²)
style="text-align: center" \| $dV$ \| differential element of volume V enclosed by surface S \| cubic meter (m³)
style="text-align: center" \| $\mathbf{E}$ \| electric field \| newton per coulomb (N⋅C⁻¹), or equivalently, volt per meter (V⋅m⁻¹)
rowspan=2 style="text-align: center" \| $E$ \| energy \| joule (J)
Young's modulus \| pascal (Pa) or newton per square meter (N/m²)
rowspan=4 style="text-align: center" \| $e$ \| eccentricity \| unitless
Euler's number (2.71828, base of the natural logarithm) \|unitless
electron \| unitless
elementary charge \| coulomb (C)
style="text-align: center" \| $\mathbf{F}$ \| force \| newton (N)
style="text-align: center" \| $F$ \| Faraday constant \| coulombs per mole (C⋅mol⁻¹)
rowspan=3 style="text-align: center" \| $f$ \| frequency \| hertz (Hz)
function \|
friction \| newton (N)
rowspan="4" style="text-align: center" \| $G$ \| electrical conductance \| siemens (S)
universal gravitational constant \| newton meter squared per kilogram squared (N⋅m²/kg²)
shear modulus \| pascal (Pa) or newton per square meter (N/m²)
gluon field strength tensor \| inverse length squared (1/m²)
style="text-align: center" \| $\mathbf{g}$ \| acceleration due to gravity \| meters per second squared (m/s²), or equivalently, newtons per kilogram (N/kg)
style="text-align: center" \| $\mathbf{H}$ \| magnetic field strength \| ampere per meter (A/m)
rowspan="3" style="text-align: center" \| $H$ \| Hamiltonian \| joule (J)
enthalpy \| joule (J)
thermal current \|watt (W)
rowspan="2" style="text-align: center" \| $h$ \| height \| meter (m)
Planck constant \| joule second (J⋅s)
style="text-align: center" \| $\hbar$ \| reduced Planck constant \| joule second (J⋅s)
rowspan=5 style="text-align: center" \| $I$ \| action \| joule second (J⋅s)
intensity \| watt per square meter (W/m²)
sound intensity \| watt per square meter (W/m²)
electric current \| ampere (A)
moment of inertia \| kilogram meter squared (kg⋅m²)
rowspan=3 style="text-align: center" \| $i$ \| intensity \| watt per square meter (W/m²)
imaginary unit \| unitless
electric current \| ampere (A)
style="text-align: center" \| $\mathbf{\hat{\imath}}$ \| Cartesian x-axis basis unit vector \| unitless
rowspan=2 style="text-align: center" \| $\mathbf{J}$ \| current density \| ampere per square meter (A/m²)
impulse \| kilogram meter per second (kg⋅m/s)
style="text-align: center" \| $\mathbf{j}$ \| jerk \| meter per second cubed (m/s³)
style="text-align: center" \| $j$ \| imaginary unit (electrical) \| unitless
style="text-align: center" \| $\mathbf{\hat{\jmath}}$ \| Cartesian y-axis basis unit vector \| unitless
style="text-align: center" \| $K$ \| kinetic energy \| joule (J)
style="text-align: center" \| $\mathbf{k}$ \| wave vector \| radian per meter (m⁻¹)
rowspan=3 style="text-align: center" \| $k$ \| Boltzmann constant \| joule per kelvin (J/K)
wavenumber \| radian per meter (m⁻¹)
stiffness \| newton per meter (N⋅m⁻¹)
style="text-align: center" \| $\mathbf{\hat{k}}$ \| Cartesian z-axis basis unit vector \| unitless
style="text-align: center" \| $\mathbf{L}$ \| angular momentum \| newton meter second (N⋅m⋅s or kg⋅m²⋅s⁻¹)
rowspan=3 style="text-align: center" \| $L$ \| inductance \| henry (H)
luminosity \| watt (W)
Lagrangian \| joule (J)
style="text-align: center" \| $\mathcal{L}$ \| Lagrangian density \| joule per cubic meter (J/m³)
style="text-align: center" \| $l$ \| length \| meter (m)
style="text-align: center" \| ℓ \| azimuthal quantum number \| unitless
style="text-align: center" \| $\mathbf{M}$ \| magnetization \| ampere per meter (A/m)
style="text-align: center" \| $M$ \| moment of force often simply called moment or torque \| newton meter (N⋅m)
style="text-align: center" \| $m$ \| mass \| kilogram (kg)
style="text-align: center" \| $\mathbf{N}$ \| normal vector \| unit varies depending on context
style="text-align: center" \| $N$ \| atomic number \| unitless
rowspan=3 style="text-align: center" \| $n$ \| refractive index \| unitless
principal quantum number \| unitless
amount of substance \| mole
rowspan="3" style="text-align: center" \| $P$ \| power \| watt (W)
active power (real power) \|watt (W)
probability \| unitless
style="text-align: center" \| $\mathbf{p}$ \| momentum \| kilogram meter per second (kg⋅m/s)
style="text-align: center" \| $p$ \| pressure \| pascal (Pa)
rowspan="3" style="text-align: center" \| $Q$ \| electric charge \| coulomb (C)
heat \| joule (J)
Reactive Power \|volt-ampere reactive (var)
style="text-align: center" \| $q$ \| electric charge \| coulomb (C)
rowspan="4" style="text-align: center" \| $R$ \| electrical resistance \| ohm (Ω)
Ricci tensor \| reciprocal square meter (m⁻²)
radiancy \| meter per second
gas constant \| joule per mole per kelvin (J⋅mol⁻¹⋅K⁻¹)
style="text-align: center" \| $\mathbf{r}$ \| radius vector (position) \| meter (m)
style="text-align: center" \| $r$ \| radius or distance \| meter (m)
rowspan="4" style="text-align: center" \| $S$ \| surface area \| square meter (m²)
entropy \| joule per kelvin (J/K)
action \| joule second (J⋅s)
apparent power (complex power) \|Volt-Ampere (VA)
style="text-align: center" \| $\mathbf{s}$ \| displacement \| meter (m)
rowspan="2" style="text-align: center" \| $s$ \| arc length \| meter (m)
distance \| meter (m)
rowspan=3 style="text-align: center" \| $T$ \| period \| second (s)
temperature \| kelvin (K) or Celsius (C)
kinetic energy \| joule (J)
style="text-align: center" \| $t$ \| time \| second (s)
style="text-align: center" \| $\mathbf{U}$ \| four-velocity \| meter per second (m/s)
rowspan=2 style="text-align: center" \| $U$ \| potential energy \| joule (J)
internal energy \| joule (J)
rowspan=3 style="text-align: center" \| $u$ \| relativistic mass \| kilogram (kg)
energy density \| joule per cubic meter (J/m³)
specific energy \| joule per kilogram (J/kg)
rowspan=3 style="text-align: center" \| $V$ \| voltage also called electric potential difference \| volt (V)
volume \| cubic meter (m³)
shear force \|
style="text-align: center" \| $\mathbf{v}$ \| velocity \| meter per second (m/s)
rowspan=2 style="text-align: center" \| $W$ \| weight \| newton (N)
mechanical work \| joule (J)
style="text-align: center" \| $w$ \| width \| meter (m)
style="text-align: center" \| $X$ \| electrical reactance \| ohm (Ω)
rowspan=2 style="text-align: center" \| $\mathbf{x}$ \| position vector \| meter (m)
displacement \| meter (m)
style="text-align: center" \| $x$ \| a generic unknown \| varied depending on context
style="text-align: center" \| $Y$ \| admittance \| siemens (S)
rowspan=2 style="text-align: center" \| $Z$ \| compressibility factor \| unitless
electrical impedance \| ohm (Ω)
style="text-align: center" \| $Z_0$ \| impedance of free space \| ohm (Ω)

class="wikitable"

Symbol

! Meaning

! SI unit of measure

style="text-align: center" |

\mathbf{A}

| magnetic vector potential

| tesla meter (T⋅m)

rowspan=3 style="text-align: center" |

A

| area

| square meter (m²)

amplitude

| meter

atomic mass number

| unitless

style="text-align: center" |

\mathbf{a}

| acceleration

| meter per second squared (m/s²)

style="text-align: center" |

\mathbf{B}

| magnetic flux density
also called the magnetic field density or magnetic induction

| tesla (T), or equivalently,
weber per square meter (Wb/m²)

rowspan=3 style="text-align: center" |

C

| capacitance

| farad (F)

heat capacity

| joule per kelvin (J⋅K⁻¹)

constant of integration

| varied depending on context

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

c

| speed of light (in vacuum)

| 299,792,458 meters per second (m/s)

speed of sound

| meter per second (m/s)

specific heat capacity

| joule per kilogram per kelvin (J⋅kg⁻¹⋅K⁻¹)

viscous damping coefficient

| kilogram per second (kg/s)

style="text-align: center" |

\mathbf{D}

| electric displacement field
also called the electric flux density

| coulomb per square meter (C/m²)

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

D

| density

| kilogram per cubic meter (kg/m³)

diameter

| meter (m)

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

d

| distance

| meter (m)

direction

| unitless

impact parameter

| meter (m)

differential (e.g.

dx

)

| varied depending on context

style="text-align: center" |

d\mathbf{A}

| differential vector element of surface area A, with infinitesimally small magnitude and direction normal to surface S

| square meter (m²)

style="text-align: center" |

dV

| differential element of volume V enclosed by surface S

| cubic meter (m³)

style="text-align: center" |

\mathbf{E}

| electric field

| newton per coulomb (N⋅C⁻¹), or equivalently, volt per meter (V⋅m⁻¹)

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

E

| energy

| joule (J)

Young's modulus

| pascal (Pa) or newton per square meter (N/m²)

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

e

| eccentricity

| unitless

Euler's number (2.71828, base of the natural logarithm)

|unitless

electron

| unitless

elementary charge

| coulomb (C)

style="text-align: center" |

\mathbf{F}

| force

| newton (N)

style="text-align: center" |

F

| Faraday constant

| coulombs per mole (C⋅mol⁻¹)

rowspan=3 style="text-align: center" |

f

| frequency

| hertz (Hz)

function

friction

| newton (N)

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

G

| electrical conductance

| siemens (S)

universal gravitational constant

| newton meter squared per kilogram squared (N⋅m²/kg²)

shear modulus

| pascal (Pa) or newton per square meter (N/m²)

gluon field strength tensor

| inverse length squared (1/m²)

style="text-align: center" |

\mathbf{g}

| acceleration due to gravity

| meters per second squared (m/s²), or equivalently, newtons per kilogram (N/kg)

style="text-align: center" |

\mathbf{H}

| magnetic field strength

| ampere per meter (A/m)

rowspan="3" style="text-align: center" |

H

| Hamiltonian

| joule (J)

enthalpy

| joule (J)

thermal current

|watt (W)

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

h

| height

| meter (m)

Planck constant

| joule second (J⋅s)

style="text-align: center" |

\hbar

| reduced Planck constant

| joule second (J⋅s)

rowspan=5 style="text-align: center" |

I

| action

| joule second (J⋅s)

intensity

| watt per square meter (W/m²)

sound intensity

| watt per square meter (W/m²)

electric current

| ampere (A)

moment of inertia

| kilogram meter squared (kg⋅m²)

rowspan=3 style="text-align: center" |

i

| intensity

| watt per square meter (W/m²)

imaginary unit

| unitless

electric current

| ampere (A)

style="text-align: center" |

\mathbf{\hat{\imath}}

| Cartesian x-axis basis unit vector

| unitless

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

\mathbf{J}

| current density

| ampere per square meter (A/m²)

impulse

| kilogram meter per second (kg⋅m/s)

style="text-align: center" |

\mathbf{j}

| jerk

| meter per second cubed (m/s³)

style="text-align: center" |

j

| imaginary unit (electrical)

| unitless

style="text-align: center" |

\mathbf{\hat{\jmath}}

| Cartesian y-axis basis unit vector

| unitless

style="text-align: center" |

K

| kinetic energy

| joule (J)

style="text-align: center" |

\mathbf{k}

| wave vector

| radian per meter (m⁻¹)

rowspan=3 style="text-align: center" |

k

| Boltzmann constant

| joule per kelvin (J/K)

wavenumber

| radian per meter (m⁻¹)

stiffness

| newton per meter (N⋅m⁻¹)

style="text-align: center" |

\mathbf{\hat{k}}

| Cartesian z-axis basis unit vector

| unitless

style="text-align: center" |

\mathbf{L}

| angular momentum

| newton meter second (N⋅m⋅s or kg⋅m²⋅s⁻¹)

rowspan=3 style="text-align: center" |

L

| inductance

| henry (H)

luminosity

| watt (W)

Lagrangian

| joule (J)

style="text-align: center" |

\mathcal{L}

| Lagrangian density

| joule per cubic meter (J/m³)

style="text-align: center" |

l

| length

| meter (m)

style="text-align: center" | ℓ

| azimuthal quantum number

| unitless

style="text-align: center" |

\mathbf{M}

| magnetization

| ampere per meter (A/m)

style="text-align: center" |

M

| moment of force
often simply called moment or torque

| newton meter (N⋅m)

style="text-align: center" |

m

| mass

| kilogram (kg)

style="text-align: center" |

\mathbf{N}

| normal vector

| unit varies depending on context

style="text-align: center" |

N

| atomic number

| unitless

rowspan=3 style="text-align: center" |

n

| refractive index

| unitless

principal quantum number

| unitless

amount of substance

| mole

rowspan="3" style="text-align: center" |

P

| power

| watt (W)

active power (real power)

|watt (W)

probability

| unitless

style="text-align: center" |

\mathbf{p}

| momentum

| kilogram meter per second (kg⋅m/s)

style="text-align: center" |

p

| pressure

| pascal (Pa)

rowspan="3" style="text-align: center" |

Q

| electric charge

| coulomb (C)

heat

| joule (J)

Reactive Power

|volt-ampere reactive (var)

style="text-align: center" |

q

| electric charge

| coulomb (C)

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

R

| electrical resistance

| ohm (Ω)

Ricci tensor

| reciprocal square meter (m⁻²)

radiancy

| meter per second

gas constant

| joule per mole per kelvin (J⋅mol⁻¹⋅K⁻¹)

style="text-align: center" |

\mathbf{r}

| radius vector (position)

| meter (m)

style="text-align: center" |

r

| radius or distance

| meter (m)

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

S

| surface area

| square meter (m²)

entropy

| joule per kelvin (J/K)

action

| joule second (J⋅s)

apparent power (complex power)

|Volt-Ampere (VA)

style="text-align: center" |

\mathbf{s}

| displacement

| meter (m)

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

s

| arc length

| meter (m)

distance

| meter (m)

rowspan=3 style="text-align: center" |

T

| period

| second (s)

temperature

| kelvin (K) or Celsius (C)

kinetic energy

| joule (J)

style="text-align: center" |

t

| time

| second (s)

style="text-align: center" |

\mathbf{U}

| four-velocity

| meter per second (m/s)

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

U

| potential energy

| joule (J)

internal energy

| joule (J)

rowspan=3 style="text-align: center" |

u

| relativistic mass

| kilogram (kg)

energy density

| joule per cubic meter (J/m³)

specific energy

| joule per kilogram (J/kg)

rowspan=3 style="text-align: center" |

V

| voltage
also called electric potential difference

| volt (V)

volume

| cubic meter (m³)

shear force

style="text-align: center" |

\mathbf{v}

| velocity

| meter per second (m/s)

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

W

| weight

| newton (N)

mechanical work

| joule (J)

style="text-align: center" |

w

| width

| meter (m)

style="text-align: center" |

X

| electrical reactance

| ohm (Ω)

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

\mathbf{x}

| position vector

| meter (m)

displacement

| meter (m)

style="text-align: center" |

x

| a generic unknown

| varied depending on context

style="text-align: center" |

Y

| admittance

| siemens (S)

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

Z

| compressibility factor

| unitless

electrical impedance

| ohm (Ω)

style="text-align: center" |

Z_0

| impedance of free space

| ohm (Ω)

Greek characters

class="wikitable"
Symbol ! Name ! Meaning ! SI unit of measure
rowspan=3 style="text-align: center" \| $\alpha$ \|rowspan=3 style="text-align: center" \|alpha \| alpha particle \|
angular acceleration \| radian per second squared (rad/s²)
fine-structure constant \| unitless
rowspan=2 style="text-align: center" \| $\beta$ \|rowspan=2 style="text-align: center" \|beta \| velocity in terms of the speed of light c \| unitless
beta particle \|
rowspan=6 style="text-align: center" \| $\gamma$ \|rowspan=6 style="text-align: center" \| gamma \| Lorentz factor \| unitless
photon \|
gamma ray \|
shear strain \| radian
heat capacity ratio \| unitless
surface tension \| newton per meter (N/m)
rowspan=2 style="text-align: center" \| $\Delta$ \|rowspan="5" style="text-align: center" \| delta \| change in a variable (e.g. $\Delta x$ ) \| unitless
Laplace operator \| per square meter (m⁻²)
rowspan="3" style="text-align: center" \| $\delta$ \| displacement (usually small) \| meter (m)
Dirac delta function \|
Kronecker delta (e.g $\delta_{ij}$ ) \|
rowspan="2" style="text-align: center" \| $\epsilon$ \|rowspan="2" style="text-align: center" \| epsilon \| permittivity \| farad per meter (F/m)
strain \| unitless
style="text-align: center" \| $\varepsilon_0$ \|style="text-align: center" \|epsilon nought \| Vacuum permittivity \| farad per meter (F/m)
style="text-align: center" \| $\zeta$ \| style="text-align: center" \| zeta \| damping ratio \| unitless
rowspan=3 style="text-align: center" \| $\eta$ \|rowspan=3 style="text-align: center" \| eta \| angular jerk \| radian per second cubed (rad⋅s⁻³)
energy efficiency \| unitless
(dynamic) viscosity (also $\mu$ ) \| pascal second (Pa⋅s)
style="text-align: center" \| $\theta$ \|style="text-align: center" \| theta \| angular displacement \| radian (rad)
style="text-align: center" \| $\kappa$ \|style="text-align: center" \| kappa \| torsion coefficient also called torsion constant \| newton meter per radian (N⋅m/rad)
style="text-align: center" \| $\Lambda$ \|rowspan=4 style="text-align: center" \| lambda \| cosmological constant \| per second squared (s⁻²)
rowspan="3" style="text-align: center" \| $\lambda$ \| wavelength \| meter (m)
linear charge density \| coulomb per meter (C/m)
eigenvalue \| non-zero vector
rowspan="6" style="text-align: center" \| $\mathbf{\mu}$ \|rowspan="6" style="text-align: center" \|mu \| magnetic moment \| ampere square meter (A⋅m²)
coefficient of friction \| unitless
(dynamic) viscosity (also $\eta$ ) \| pascal second (Pa⋅s)
permeability (electromagnetism) \| henry per meter (H/m)
reduced mass \| kilogram (kg)
Standard gravitational parameter \| cubic meter per second squared
style="text-align: center" \| $\mathbf{\mu}_0$ \|style="text-align: center" \|mu nought \| Vacuum permeability or the magnetic constant \| henry per meter (H/m)
rowspan=3 style="text-align: center" \| $\nu$ \|rowspan=3 style="text-align: center" \| nu \| frequency \| hertz (Hz)
kinematic viscosity \| meter squared per second (m²/s)
neutrino \|
style="text-align: center" \| $\xi$ \|style="text-align: center" \| xi \| electromotive force \| volt (V)
style="text-align: center" \| $\pi$ \|style="text-align: center" \| pi \| 3.14159... (irrational number) \| unitless
rowspan=3 style="text-align: center" \| $\rho$ \|rowspan=3 style="text-align: center" \| rho \| mass density usually simply called density \| kilogram per cubic meter (kg/m³)
volume charge density \| coulomb per cubic meter (C/m³)
resistivity \| ohm meter (Ω⋅m)
style="text-align: center" \| $\Sigma$ \|rowspan=6 style="text-align: center" \| sigma \| summation operator \|
rowspan=5 style="text-align: center" \| $\sigma$ \| area charge density \| coulomb per square meter (C/m²)
electrical conductivity \| siemens per meter (S/m)
normal stress \| pascal (Pa)
scattering cross section \| barn (10^-28 m^2)
surface tension \| newton per meter (N/m)
rowspan=4 style="text-align: center" \| $\tau$ \|rowspan=4 style="text-align: center" \| tau \| torque \| newton meter (N⋅m)
shear stress \| pascal (Pa)
time constant \| second (s)
6.28318... (2π) \| unitless
rowspan=2 style="text-align: center" \| $\Phi$ \|rowspan=4 style="text-align: center" \| phi \| field strength \| unit varies depending on context
magnetic flux \| weber (Wb)
rowspan=2 style="text-align: center" \| $\phi$ \| electric potential \| volt (V)
Higgs field work function \|
style="text-align: center" \| $\Psi$ \|style="text-align: center" \| psi \| wave function \| m^−3/2
style="text-align: center" \| $\Omega$ \| rowspan="3" style="text-align: center" \|omega \| electric resistance \| ohm
rowspan="2" style="text-align: center" \| $\omega$ \| angular frequency \| radian per second (rad/s)
angular velocity \|radian per second (rad/s)

class="wikitable"

Symbol

! Name

! Meaning

! SI unit of measure

rowspan=3 style="text-align: center" |

\alpha

|rowspan=3 style="text-align: center" |alpha

| alpha particle

angular acceleration

| radian per second squared (rad/s²)

fine-structure constant

| unitless

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

\beta

|rowspan=2 style="text-align: center" |beta

| velocity in terms of the speed of light c

| unitless

beta particle

rowspan=6 style="text-align: center" |

\gamma

|rowspan=6 style="text-align: center" | gamma

| unitless

| radian

| unitless

| newton per meter (N/m)

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

\Delta

|rowspan="5" style="text-align: center" | delta

| change in a variable (e.g. $\Delta x$ )

| unitless

Laplace operator

| per square meter (m⁻²)

rowspan="3" style="text-align: center" |

\delta

| displacement (usually small)

| meter (m)

Dirac delta function

Kronecker delta (e.g

\delta_{ij}

)

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

\epsilon

|rowspan="2" style="text-align: center" | epsilon

| permittivity

| farad per meter (F/m)

strain

| unitless

style="text-align: center" |

\varepsilon_0

|style="text-align: center" |epsilon nought

| Vacuum permittivity

| farad per meter (F/m)

style="text-align: center" |

\zeta

| style="text-align: center" | zeta

| damping ratio

| unitless

rowspan=3 style="text-align: center" |

\eta

|rowspan=3 style="text-align: center" | eta

| angular jerk

| radian per second cubed (rad⋅s⁻³)

energy efficiency

| unitless

(dynamic) viscosity (also

\mu

)

| pascal second (Pa⋅s)

style="text-align: center" |

\theta

|style="text-align: center" | theta

| angular displacement

| radian (rad)

style="text-align: center" |

\kappa

|style="text-align: center" | kappa

| torsion coefficient
also called torsion constant

| newton meter per radian (N⋅m/rad)

style="text-align: center" |

\Lambda

|rowspan=4 style="text-align: center" | lambda

| cosmological constant

| per second squared (s⁻²)

rowspan="3" style="text-align: center" |

\lambda

| wavelength

| meter (m)

linear charge density

| coulomb per meter (C/m)

eigenvalue

| non-zero vector

rowspan="6" style="text-align: center" |

\mathbf{\mu}

|rowspan="6" style="text-align: center" |mu

| magnetic moment

| ampere square meter (A⋅m²)

coefficient of friction

| unitless

(dynamic) viscosity (also

\eta

)

| pascal second (Pa⋅s)

permeability (electromagnetism)

| henry per meter (H/m)

reduced mass

| kilogram (kg)

Standard gravitational parameter

| cubic meter per second squared

style="text-align: center" |

\mathbf{\mu}_0

|style="text-align: center" |mu nought

| Vacuum permeability or the magnetic constant

| henry per meter (H/m)

rowspan=3 style="text-align: center" |

\nu

|rowspan=3 style="text-align: center" | nu

| frequency

| hertz (Hz)

kinematic viscosity

| meter squared per second (m²/s)

neutrino

style="text-align: center" |

\xi

|style="text-align: center" | xi

| electromotive force

| volt (V)

style="text-align: center" |

\pi

|style="text-align: center" | pi

| 3.14159... (irrational number)

| unitless

rowspan=3 style="text-align: center" |

\rho

|rowspan=3 style="text-align: center" | rho

| mass density
usually simply called density

| kilogram per cubic meter (kg/m³)

volume charge density

| coulomb per cubic meter (C/m³)

resistivity

| ohm meter (Ω⋅m)

style="text-align: center" |

\Sigma

|rowspan=6 style="text-align: center" | sigma

| summation operator

rowspan=5 style="text-align: center" |

\sigma

| area charge density

| coulomb per square meter (C/m²)

electrical conductivity

| siemens per meter (S/m)

normal stress

| pascal (Pa)

scattering cross section

| barn (10^-28 m^2)

surface tension

| newton per meter (N/m)

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

\tau

|rowspan=4 style="text-align: center" | tau

| torque

| newton meter (N⋅m)

shear stress

| pascal (Pa)

time constant

| second (s)

6.28318... (2π)

| unitless

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

\Phi

|rowspan=4 style="text-align: center" | phi

| field strength

| unit varies depending on context

magnetic flux

| weber (Wb)

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

\phi

| electric potential

| volt (V)

Higgs field work function

style="text-align: center" |

\Psi

|style="text-align: center" | psi

| wave function

| m^−3/2

style="text-align: center" |

\Omega

| rowspan="3" style="text-align: center" |omega

| electric resistance

| ohm

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

\omega

| angular frequency

| radian per second (rad/s)

angular velocity

|radian per second (rad/s)

Other characters

class = wikitable
Symbol ! Name ! Meaning ! SI unit of measure
style="text-align: center" \| $\nabla\cdot$ \| style="text-align: center" \| nabla dot \| the divergence operator often pronounced "del dot" \| per meter (m⁻¹)
style="text-align: center" \| $\nabla\times$ \| style="text-align: center" \| nabla cross \|the curl operator often pronounced "del cross" \|per meter (m⁻¹)
style="text-align: center" \| $\nabla$ \| style="text-align: center" \| nabla \| delta (differential operator) \|
the area of a shape \| style="text-align: center" \| $\partial$ \| "der", "dow", "die", "partial" or simply "d" \|partial derivative (e.g. $\partial y/\partial x$ ) \|
style="text-align: center" \| $\Box$ \| style="text-align: center" \| D'Alembert operator \| $\nabla^2-\partial_t^2$ \|
style="text-align: center" \| $\langle \, \, \rangle$ \|rowspan=2 style="text-align: center" \| angle brackets \| average sometimes over Maxwell–Boltzmann distribution \|
style="text-align: center" \| $\langle \ \| \ \rangle$ \| Dirac notation \|
style="text-align: center" \| $\int$ \|integral \|the inverse of the derivative. \|unitless

class = wikitable

Symbol

! Name

! Meaning

! SI unit of measure

style="text-align: center" |

\nabla\cdot

| style="text-align: center" | nabla dot

| the divergence operator
often pronounced "del dot"

| per meter (m⁻¹)

style="text-align: center" |

\nabla\times

| style="text-align: center" | nabla cross

|the curl operator
often pronounced "del cross"

|per meter (m⁻¹)

style="text-align: center" |

\nabla

| style="text-align: center" | nabla

| delta (differential operator)

the area of a shape

| style="text-align: center" | $\partial$

| "der", "dow", "die", "partial" or simply "d"

|partial derivative (e.g. $\partial y/\partial x$ )

style="text-align: center" |

\Box

| style="text-align: center" | D'Alembert operator

| $\nabla^2-\partial_t^2$

style="text-align: center" |

\langle \, \, \rangle

|rowspan=2 style="text-align: center" | angle brackets

| average
sometimes over Maxwell–Boltzmann distribution

style="text-align: center" |

\langle \  | \ \rangle

| Dirac notation

style="text-align: center" |

\int

|integral

|the inverse of the derivative.

|unitless

References

{{Cite web|last=Elert|first=Glenn|title=Special Symbols|url=https://physics.info/symbols/|website=The Physics Hypertextbook|access-date=4 August 2021}}
{{Cite web|author=NIST|title=SI Units|date=16 August 2023|url=https://www.nist.gov/pml/owm/metric-si/si-units|website=www.nist.gov|publisher=NIST}}

Common Physics Abbreviations

List of common physics notations

Latin characters

Greek characters

Other characters

See also

References