Greek Alphabet Chart: Letters, Names and Engineering Symbols
Greek alphabet chart: capital and lowercase forms of all 24 letters, their names in six languages and the engineering meanings of ρ, σ, τ, η, μ and ω.
For reference. Symbol meanings vary by field and publication, so check the standard or text you work from.
Columns
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| Capital letter | Lowercase letter | Other form | Turkish | English | Spanish | Portuguese | German | French | Common engineering meanings |
|---|---|---|---|---|---|---|---|---|---|
| Α | α | no value | Alfa | Alpha | Alfa | Alfa | Alpha | Alpha | angle, angular acceleration, thermal expansion coefficient |
| Β | β | no value | Beta | Beta | Beta | Beta | Beta | Bêta | angle, transistor current gain |
| Γ | γ | no value | Gama | Gamma | Gamma | Gama | Gamma | Gamma | shear strain, specific weight, heat capacity ratio |
| Δ | δ | no value | Delta | Delta | Delta | Delta | Delta | Delta | Δ difference or change, δ infinitesimal change, loss angle |
| Ε | ε | ϵ | Epsilon | Epsilon | Épsilon | Épsilon | Epsilon | Epsilon | strain, permittivity, emissivity |
| Ζ | ζ | no value | Zeta | Zeta | Dseta | Dzeta | Zeta | Zêta | damping ratio, zeta potential |
| Η | η | no value | Eta | Eta | Eta | Eta | Eta | Êta | efficiency, dynamic viscosity |
| Θ | θ | ϑ | Teta | Theta | Zeta | Teta | Theta | Thêta | angle, Celsius temperature, thermal resistance |
| Ι | ι | no value | İota | Iota | Iota | Iota | Iota | Iota | not a common engineering symbol |
| Κ | κ | ϰ | Kappa | Kappa | Kappa | Capa | Kappa | Kappa | curvature, conductivity, heat capacity ratio |
| Λ | λ | no value | Lambda | Lambda | Lambda | Lambda | Lambda | Lambda | wavelength, thermal conductivity, eigenvalue, failure rate |
| Μ | μ | no value | Mü | Mu | Mi | Mi | My | Mu | dynamic viscosity, friction coefficient, micro prefix, magnetic permeability |
| Ν | ν | no value | Nü | Nu | Ni | Ni | Ny | Nu | kinematic viscosity, Poisson's ratio, frequency |
| Ξ | ξ | no value | Ksi | Xi | Xi | Csi | Xi | Xi | damping ratio, extent of reaction |
| Ο | ο | no value | Omikron | Omicron | Ómicron | Ômicron | Omikron | Omicron | not a common engineering symbol, looks like the Latin letter O |
| Π | π | ϖ | Pi | Pi | Pi | Pi | Pi | Pi | ratio of circumference to diameter, Π product sign, osmotic pressure |
| Ρ | ρ | ϱ | Ro | Rho | Ro | Rô | Rho | Rhô | density, resistivity, charge density |
| Σ | σ | ς | Sigma | Sigma | Sigma | Sigma | Sigma | Sigma | normal stress, standard deviation, electrical conductivity, Σ summation sign |
| Τ | τ | no value | Tau | Tau | Tau | Tau | Tau | Tau | shear stress, time constant, mean lifetime |
| Υ | υ | no value | Üpsilon | Upsilon | Ípsilon | Ípsilon | Ypsilon | Upsilon | not a common engineering symbol |
| Φ | φ | ϕ | Fi | Phi | Fi | Fi | Phi | Phi | angle, phase angle, electric potential, Φ magnetic flux |
| Χ | χ | no value | Ki | Chi | Ji | Qui | Chi | Khi | magnetic susceptibility, chi squared distribution, buckling reduction factor |
| Ψ | ψ | no value | Psi | Psi | Psi | Psi | Psi | Psi | wavefunction, stream function, Ψ electric flux |
| Ω | ω | no value | Omega | Omega | Omega | Ômega | Omega | Oméga | angular velocity, Ω ohm, solid angle |
Quick answers
- ε (Ε): English Epsilon, Turkish Epsilon. Common engineering meanings: strain, permittivity, emissivity. View in table
- η (Η): English Eta, Turkish Eta. Common engineering meanings: efficiency, dynamic viscosity. View in table
- μ (Μ): English Mu, Turkish Mü. Common engineering meanings: dynamic viscosity, friction coefficient, micro prefix, magnetic permeability. View in table
- ν (Ν): English Nu, Turkish Nü. Common engineering meanings: kinematic viscosity, Poisson's ratio, frequency. View in table
- ρ (Ρ): English Rho, Turkish Ro. Common engineering meanings: density, resistivity, charge density. View in table
- σ (Σ): English Sigma, Turkish Sigma. Common engineering meanings: normal stress, standard deviation, electrical conductivity, Σ summation sign. View in table
- τ (Τ): English Tau, Turkish Tau. Common engineering meanings: shear stress, time constant, mean lifetime. View in table
- ω (Ω): English Omega, Turkish Omega. Common engineering meanings: angular velocity, Ω ohm, solid angle. View in table
Conditions and notes
The 24 standard Greek letters. Names follow the dictionary spelling of each language and meanings come from physics, chemistry and engineering reference works.
- Turkish names are not written the same way everywhere. Next to the Kappa, Lambda and Üpsilon used here, the forms kapa, lamda and ipsilon or upsilon also occur.
- The Spanish column uses the names in the dictionary of the Spanish language academy, so Ζ is written dseta and Θ zeta. The Portuguese column follows Brazilian dictionaries, for example dzeta, capa, csi and qui.
- In the French column xi is also written ksi, zêta also dzéta and khi also chi.
- ε and ϵ, θ and ϑ, κ and ϰ, π and ϖ, ρ and ϱ, σ and ς, φ and ϕ are separate Unicode characters. The second form appears in the Other form column. Depending on the typeface the two forms can look alike.
The Greek alphabet has 24 letters, and engineers, physicists and mathematicians use them as variable names. The table lists the capital and lowercase form of each letter, its name in Turkish, English, Spanish, Portuguese, German and French, and the meanings engineers meet most often. For example ρ stands for density or resistivity, σ for normal stress, τ for shear stress and ω for angular velocity.
The same letter can stand for different quantities depending on the field. μ is dynamic viscosity in one text, and a friction coefficient or the micro prefix in another. For this reason always check the symbol list of the publication you work from to see which quantity a letter means in a formula. The table lists only common meanings found in reference works, not every use of a letter, and none of them is a required choice of a standard.
Some letters have more than one written form. ε and ϵ, θ and ϑ, ρ and ϱ, φ and ϕ are separate Unicode characters, and depending on the typeface the two forms can look alike. Sigma takes the form ς at the end of a word.
Sources
This table is for preliminary reference. Check the applicable standard and product conditions before use.
- Source 1. UNICODE 18.0.0. Accessed: 2026-10-16
- Source 2. HTML LIVING STANDARD. Accessed: 2026-10-16
- Source 3. ONLINE EDITION. Accessed: 2026-10-16
- Source 4. ONLINE PAGE. Accessed: 2026-10-16
- Source 5. 8 FEB 2024. Accessed: 2026-10-16
- Source 6. ONLINE PAGE. Accessed: 2026-10-16
- Source 7. 5TH EDITION 2022. Accessed: 2026-10-16
- Source 8. EDICION DEL TRICENTENARIO. Accessed: 2026-10-16
- Source 9. ONLINE PAGE. Accessed: 2026-10-16
- Source 10. ONLINE PAGE. Accessed: 2026-10-16
- Source 11. ONLINE PAGE. Accessed: 2026-10-16
- Source 12. ONLINE PAGE. Accessed: 2026-10-16
- Source 13. ONLINE PAGE. Accessed: 2026-10-16
- Source 14. ONLINE PAGE. Accessed: 2026-10-16
- Source 15. ONLINE PAGE. Accessed: 2026-10-16
- Source 16. ONLINE PAGE. Accessed: 2026-10-16
- Source 17. ONLINE PAGE. Accessed: 2026-10-16
- Source 18. ONLINE PAGE. Accessed: 2026-10-16
- Source 19. 3RD EDITION 2007. Accessed: 2026-10-16
- Source 20. NIST SP 330 2019 EDITION. Accessed: 2026-10-16
- Source 21. ONLINE PAGE. Accessed: 2026-10-16
- Source 22. 28 JAN 2021. Accessed: 2026-10-16
Data version: 2026-10-16