### Commonly Used Greek Letters in Subjects

Commonly Used Greek Letters in Subjects

Lower case

Capital

Name

$\alpha\;$$\Alpha\;$alphaAngular acceleration
Linear expansion
Coefficient
Alpha particle (helium nucleus)
Fine Structure Constant
$\beta\;$$\Beta\;$betaBeta particle — high energy electron
Sound intensity
$\gamma\;$$\Gamma\;$gammaGamma ray (high energy EM wave)
Ratio of heat capacities (in an ideal gas)
Relativistic correction factor
$\delta\;$$\Delta\;$deltaΔ="Change in"
δ="Infinitessimal change in"
$\epsilon\;$$\Epsilon\;$epsilonEmissivity
Strain
Permittivity
EMF
$\zeta\;$$\Zeta\;$zeta(no common use)
$\eta\;$$\Eta\;$etaViscosity
Energy efficiency
$\theta\;$$\Theta\;$thetaAngle (°, rad)
Temperature
$\iota\;$$\Iota\;$iotaThe lower case $\iota\;$ is rarely used, while $\Iota\;$ is sometimes used for the identity matrix or the moment of inertia. Note that $\iota\;$ is not to be confused with the Roman character i; (which has a dot and is much more widely used in mathematics and physics).
$\kappa\;$$\Kappa\;$kappaSpring constant
Dielectric constant
$\lambda\;$$\Lambda\;$lambdaWavelength
Thermal conductivity
Constant
Eigenvalue of a matrix
Linear density
$\mu\;$$\Mu\;$muCoefficient of friction
Electrical mobility
Reduced mass
Permeability
$\nu\;$$\Nu\;$nuFrequency
$\xi\;$$\Xi\;$xiDamping cofficient
$o\;$$O\;$omicron(no common use)
$\pi\;$$\Pi\;$piProduct symbol Π
Circle number π: = 3.14159...
$\rho\;$$\Rho\;$rhoVolume density
Resistivity
$\sigma\;$$\Sigma\;$sigmaSum symbol
Boltzmann constant
Electrical conductivity
Uncertainty
Stress
Surface density
$\tau\;$$\Tau\;$tauTorque
Tau particle (a lepton)
Time constant
$\upsilon\;$$\Upsilon\;$upsilon(pending)
$\phi\;$$\Phi\;$phiMagnetic/electric flux
$\chi\;$$\Chi\;$chiRabi frequency (lasers)
$\psi\;$$\Psi\;$psiWave function
$\omega\;$$\Omega\;$omegaOhms (unit of electrical resistance)