Greek Alphabet Reference
The 24 letters of the Greek alphabet, with their uppercase and lowercase forms, their names, and the fields that borrow them.
At a glance
Key facts- Letters
- 24, alpha to omega
- First vowels
- First true alphabet
- Descendants
- Latin and Cyrillic
- Everyday use
- Math, physics, science
The 24 Greek letters
24 rows| Upper | Lower | Name | Code points | HTML entity | LaTeX | What it usually means |
|---|---|---|---|---|---|---|
| Α | α | Alpha | U+0391 / U+03B1 | Α α | \alpha | Angle, coefficient, significance level |
| Β | β | Beta | U+0392 / U+03B2 | Β β | \beta | Angle, beta particle, regression coefficient |
| Γ | γ | Gamma | U+0393 / U+03B3 | Γ γ | \Gamma \gamma | Gamma ray, Lorentz factor, gamma function |
| Δ | δ | Delta | U+0394 / U+03B4 | Δ δ | \Delta \delta | Change or difference, Dirac delta |
| Ε | ε | Epsilon | U+0395 / U+03B5 | Ε ε | \epsilon | A vanishingly small quantity, permittivity |
| Ζ | ζ | Zeta | U+0396 / U+03B6 | Ζ ζ | \zeta | Damping ratio, Riemann zeta function |
| Η | η | Eta | U+0397 / U+03B7 | Η η | \eta | Efficiency, viscosity |
| Θ | θ | Theta | U+0398 / U+03B8 | Θ θ | \Theta \theta | Angle, temperature, asymptotic bound |
| Ι | ι | Iota | U+0399 / U+03B9 | Ι ι | \iota | A tiny amount, inclusion map |
| Κ | κ | Kappa | U+039A / U+03BA | Κ κ | \kappa | Curvature, thermal conductivity |
| Λ | λ | Lambda | U+039B / U+03BB | Λ λ | \Lambda \lambda | Wavelength, eigenvalue, rate parameter |
| Μ | μ | Mu | U+039C / U+03BC | Μ μ | \mu | Micro prefix, population mean, friction coefficient |
| Ν | ν | Nu | U+039D / U+03BD | Ν ν | \nu | Frequency, kinematic viscosity |
| Ξ | ξ | Xi | U+039E / U+03BE | Ξ ξ | \Xi \xi | Random variable, damping ratio |
| Ο | ο | Omicron | U+039F / U+03BF | Ο ο | uses the Latin letter | Rarely used alone, it looks like the letter o |
| Π | π | Pi | U+03A0 / U+03C0 | Π π | \Pi \pi | Circle constant, and the product operator in capital form |
| Ρ | ρ | Rho | U+03A1 / U+03C1 | Ρ ρ | \rho | Density, resistivity, correlation coefficient |
| Σ | σ | Sigma | U+03A3 / U+03C3 | Σ σ | \Sigma \sigma | Standard deviation, and the sum operator in capital form |
| Τ | τ | Tau | U+03A4 / U+03C4 | Τ τ | \tau | Time constant, torque, shear stress |
| Υ | υ | Upsilon | U+03A5 / U+03C5 | Υ υ | \Upsilon \upsilon | Upsilon particle in physics |
| Φ | φ | Phi | U+03A6 / U+03C6 | Φ φ | \Phi \phi | Golden ratio, angle, magnetic flux |
| Χ | χ | Chi | U+03A7 / U+03C7 | Χ χ | \chi | The chi-squared test, characteristic function |
| Ψ | ψ | Psi | U+03A8 / U+03C8 | Ψ ψ | \Psi \psi | Wave function |
| Ω | ω | Omega | U+03A9 / U+03C9 | Ω ω | \Omega \omega | Angular frequency, and ohms in capital form |
The LaTeX column is the standard control sequence and is editorial: no machine readable authority for it was read. The code points and the HTML entities are taken from the Unicode database and the WHATWG entity list.
Source: Unicode Greek and Coptic block, U+0370 to U+03FF. Checked against that source on . 24 letters, dataset version 1.1.0. Changelog and JSON.
Where it comes from
The Greek alphabet took shape around the ninth century BCE, when Greeks adapted the Phoenician consonant script and, crucially, added dedicated letters for vowels. That made it the first alphabet in the modern sense, and it became the direct ancestor of the Latin and Cyrillic alphabets. The same 24 letters are still written today, in Greece for the modern language and everywhere else as a shared pool of symbols for mathematics, physics, engineering, and the sciences.
How to use it
Read each row as a pair: the capital form on the left, the small form beside it, then the name you say aloud. Many letters carry fixed meanings by convention. Pi is the circle constant, sigma marks a sum in its capital form and standard deviation in its lowercase form, theta is an angle, lambda a wavelength, and delta a change or difference. When you meet a Greek letter in a formula, its name is usually the fastest way to look up what it stands for, so knowing the names matters as much as recognizing the shapes.
This page is a standing reference at a fixed URL, built to be linked and cited. The data here is compiled from the standard Greek alphabet as used in mathematics, science, and modern Greek.