| α | Alpha | Fine structure constant; an angle. | 
| ß | Beta | v/c; 1/κBΤ ; an angle. | 
| γ | Gamma | E/mc2; an angle. | 
| τ | Tau | torque; a rate of force. | 
| Τ | Tau | Periodic time. | 
| Δ | Delta | 'change in . . . ', as in Δx. | 
| δ | Delta | An infinitesimal; like Δ but smaller. | 
| σ | Delta | Cross section; areal density; conductivity. | 
|  | Epsilon | An infinitesimal quantity; permittivity. | 
| e | e | A small energy, electron. | 
| ζ | Zeta | A general parameter. | 
| η | Eta | Index of refraction; a meson. | 
| Θ | Null | An angle; Debye temperature. | 
| θ | Theta | An angle (most common symbol). | 
| κ | Kappa | Dielectric constant; thermal conductivity. | 
| Λ | Lambda | A rate; a type of baryon. | 
| λ | Lambda | Wavelength; a rate; linear density. | 
| μ | Meu | Reduced mass; muon; prefix micro. | 
| ν | Nu | Frequency in cycle/s (Hz); neutrino. | 
| v | Nu | Rarely used (looks like v). | 
| Ξ | Xi | A type of baryon. | 
| ξ | Xi | A general parameter; coherence length. | 
| Π | Pi | Product operator. | 
| π | Pi | 3.14159... ; pion (a meson). | 
| ρ | Rho | Density per unit volume; resistivity. | 
| Σ | Sigma | Summation operator. | 
| Φ | Phi | A wave function; an angle. | 
|  | Phi | An angle; a wave function. | 
| φ | Phi | Electrostatic potential. | 
| χ | Chi | Susceptibility. | 
| ψ | Psi | A wave function. | 
|  | Mho | Used as inductance. | 
| Ω | Ohm | Solid angle; angular frequency; a baryon. | 
| ω | Omega | Angular frequency (radian/s); a meson.Cube root of unity.
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