Physics Study Guide/Greek alphabet

About the Common uses in Physics

While these are indeed common usages, it should be pointed out that there are many other usages and that other letters are used for the same purpose. The reason is quite simple: there are only so many symbols in the Greek and Latin alphabets, and scientists and mathematicians generally do not use symbols from other languages. It is a common trap to associate a symbol exclusively with some particular meaning, rather than learning and understanding the physics and relations behind it.

Greek Alphabet

Lower case	Capital	Name	Common use in Physics
$\alpha$	$\mathrm{A}$	alpha	Angular acceleration Linear expansion Coefficient Alpha particle (helium nucleus) Fine Structure Constant
$\beta$	$\mathrm{B}$	beta	Beta particle — high energy electron Sound intensity
$\gamma$	$\mathrm{\Gamma }$	gamma	Gamma ray (high energy EM wave) Ratio of heat capacities (in an ideal gas) Relativistic correction factor
$\delta$	$\mathrm{\Delta }$	delta	Δ="Change in" δ="Infinitessimal change in"
$ϵ$	$\mathrm{E}$	epsilon	Emissivity Strain Permittivity EMF
$\zeta$	$\mathrm{Z}$	zeta	(no common use)
$\eta$	$\mathrm{H}$	eta	Viscosity Energy efficiency
$\theta$	$\mathrm{\Theta }$	theta	Angle (°, rad) Temperature
$\iota$	$\mathrm{I}$	iota	Imaginary unit ($\iota :=\sqrt{-1}$)
$\kappa$	$\mathrm{K}$	kappa	Spring constant
$\lambda$	$\mathrm{\Lambda }$	lambda	Wavelength Thermal conductivity Constant Eigenvalue of a matrix Linear density
$\mu$	$\mathrm{M}$	mu	Coefficient of friction Reduced mass Permeability
$\nu$	$\mathrm{N}$	nu	Frequency
$\xi$	$\mathrm{\Xi }$	xi	Damping cofficient
$o$	$O$	omicron	(no common use)
$\pi$	$\mathrm{\Pi }$	pi	Product symbol $\mathrm{\Pi }$ Circle number $\pi :=3.14159...$
$\rho$	$\mathrm{P}$	rho	Volume density Resistivity
$\sigma$	$\mathrm{\Sigma }$	sigma	Sum symbol Boltzmann constant Uncertainty Stress Surface density
$\tau$	$\mathrm{T}$	tau	Torque Tau particle (a lepton) Time constant
$\upsilon$	$\mathrm{{\rm Y}}$	upsilon	(pending)
$\varphi$	$\mathrm{\Phi }$	phi	Magnetic/electric flux Angle (°, rad)
$\chi$	$\mathrm{X}$	chi	Rabi frequency (lasers) Susceptibility
$\psi$	$\mathrm{\Psi }$	psi	Wave function
$\omega$	$\mathrm{\Omega }$	omega	Ohms (unit of electrical resistance) ω Angular velocity

See Also

Greek alphabet on the Wikipedia