# Greek Alphabets Used in Physics

The following is the table showing the “most commonly used” Greek Alphabets and their typical meaning in Physics. Also lists the Physical Constants which they typically represent.

Greek Letter Upper Case Lower Case Commonly Represents in Physics
Alpha $A$ $\alpha$ Angular acceleration
Linear Expansion
Coefficient
Alpha particle (helium nucleus)
Fine Structure Constant
Beta $B$ $\beta$ Beta particle (high energy electron)
Sound intensity
Gamma $\Gamma$ $\gamma$ Gamma ray (high energy EM wave)
Ratio of heat capacities (in an ideal gas)
Relativistic correction factor
Delta $\Delta$ $\delta$ $\Delta$ – Change
$\delta$ – Infinitesimal change
Epsilon $E$ $\epsilon ~/~ \varepsilon$ Emissivity
Strain
Permittivity
EMF
Zeta $Z$ $\zeta$ Damping ratio
Coefficient of viscous friction in polymers
Relative Vertical Vorticity in Fluid Dynamics
Eta $H$ $\eta$ Viscosity
Energy efficiency
Theta $\Theta$ $\theta ~/~ \vartheta$ Angle
Temperature
Iota $I$ $\iota$ Identity Matrix
Moment of Inertia
Kappa $K$ $\kappa$ Spring constant
Dielectric constant
Lambda $\Lambda$ $\lambda$ Wavelength
Thermal conductivity
Constant
Linear Density
Mu $M$ $\mu$ Coefficient of friction
Electrical mobility
Reduced mass
Permeability
Nu $N$ $\nu$ Frequency
Xi $\Xi$ $\xi$ Damping coefficient
Omicron $O$ $o$ {not commonly used}
Pi $\Pi$ $\pi$ $\pi~=~3.14159 \cdots$
Rho $P$ $\rho ~/~ \varrho$ Volume density
Resistivity
Sigma $\Sigma$ $\sigma$ Boltzmann constant
Electrical conductivity
Uncertainty
Stress
Surface density
Tau $T$ $\tau$ Torque
Tau particle (a lepton)
Time constant
Upsilon $\Upsilon$ $\upsilon$ mass to light ratio
Phi $\Phi$ $\phi ~/~ \varphi$ Magnetic / electric flux
Angle
Chi $X$ $\chi$ Susceptibility
Psi $\Psi$ $\psi$ Wave function
Omega $\Omega$ $\omega$ Ohms (unit of electric resistance)
$\omega$ – Angular velocity