📂Writing

How to Read and Write Greek Characters and Their Meaning in Mathematics and Science

Alpha $\Alpha, \alpha$

Alpha is read as “alpha”. The TeX codes are \Alpha, \alpha respectively.

It is the first letter of the Greek alphabet, and the phrase “alpha and omega” means “the beginning and the end.”

• Index of an index set $\alpha$
• In differential geometry, a curve $\alpha$
• Curve used to define tangent vectors on a differential manifold $\alpha$

Beta $\Beta, \beta$

Beta is read as “beta”. The TeX codes are \Beta, \beta respectively.

• Beta function $B$

Gamma $\Gamma, \gamma$

Gamma is read as “gamma”. The TeX codes are \Gamma, \gamma respectively.

• Gamma function $\Gamma$
• In differential geometry, a curve $\gamma$
• Christoffel symbols $\Gamma_{ij}^{k}$

Delta $\Delta, \delta$

Delta is read as “delta”. The TeX codes are \Delta, \delta respectively.

• In calculus, a very small change $x$ $\Delta x$
• In physics, the Laplacian $\Delta$
• In partial differential equations, the Laplacian $\Delta$
• In mathematics, a very small positive number $\delta$: $\epsilon - \delta$ argument
• Dirac delta function $\delta$
• Kronecker delta $\delta_{ij}$

Epsilon $\Epsilon, \epsilon, \varepsilon$

Epsilon is read as “epsilon”. The TeX codes are \Epsilon, \epsilon, \varepsilon respectively.

Although the correct pronunciation is epsilon, it is often pronounced as upsilon.

• In mathematics, a very small positive number $\epsilon$: $\epsilon - \delta$ argument
• In electromagnetism, the permittivity $\epsilon$
• Levi-Civita symbol $\epsilon_{ijk}$

Zeta $\Zeta, \zeta$

Zeta is read as “zeta”. The TeX codes are \Zeta, \zeta respectively.

It is not widely used. Often used when running out of variables.

• Riemann zeta function $\zeta$

Eta $\Eta, \eta$

Eta is read as “eta”. The TeX codes are \Eta, \eta respectively.

Like zeta, it is used when there are no suitable variables available.

• In particle physics, a baryon $\eta$

Theta $\Theta, \theta, \vartheta$

Theta is read as “theta”. The TeX codes are \Theta, \theta, \vartheta respectively.

It is mostly considered to represent an angle.

• Angle $\theta$
• In variable separation, a function that has $\theta$ as a variable $\Theta (\theta)$

Iota $\Iota, \iota$

Iota is read as “iota”. The TeX codes are \Iota, \iota respectively.

It is not commonly used.

Kappa $\Kappa, \kappa$

Kappa is read as “kappa”. The TeX codes are \Kappa, \kappa respectively.

• In differential geometry, curvature $\kappa$:
  Normal curvature $\kappa _{n}$, Geodesic curvature $\kappa_{g}$, [Principal curvature $\kappa$]
• In quantum mechanics, a substitution constant for negative energy $\kappa$](../1261)

Lambda $\Lambda, \lambda$

Lambda is read as “lambda”. The TeX codes are \Lambda, \lambda respectively.

• Eigenvalue $\lambda$
• In physics, wavelength $\lambda$

Mu $\Mu, \mu$

Mu is read as “mu”. The TeX codes are \Mu, \mu respectively.

• Measure $\mu$
• In electromagnetism, permeability $\mu$
• In particle physics, a muon $\mu$
• In statistics, mean $\mu$

Nu $\Nu, \nu$

Nu is read as “nu”. The TeX codes are \Nu, \nu respectively.

• In physics, frequency $\nu$
• In particle physics, neutrino $\nu$

Xi $\Xi, \xi$

Xi is read as “xi”, also pronounced as “ksi” or “zai”. It’s the Xi apartment’s “Xi”. The TeX codes are \Xi, \xi respectively.

It is often used when running out of variables.

• Variable for the Fourier transform of $x$ $\xi$
• Riemann Xi function $\xi$

Omicron $\Omicron, \omicron$

Omicron is pronounced as “Omicron” and is almost the same shape as the alphabet $o$, so it is not used. The TeX codes are \Omicron, \omicron respectively.

Pi $\Pi, \pi$

Pi is pronounced as “pi” and represents the mathematical constant pi. The TeX codes are \Pi, \pi respectively.

• Product symbol $\Pi$
• Pi, the mathematical constant $\pi$
• In particle physics, a pion meson $\pi$

Rho $\Rho, \rho$

Rho is pronounced as “rho”. The TeX codes are \Rho, \rho respectively.

• Radius variable in cylindrical coordinates $\rho$](../1795)
• In physics, density $\rho$
  Volume charge density $\rho$

Sigma $\Sigma, \sigma$

Sigma is pronounced as “sigma”. The TeX codes are \Sigma, \Sigma respectively.

• Summation symbol $\Sigma$
• Variance in statistics $\sigma^{2}$
• In electromagnetism, surface charge density $\sigma$
• In thermodynamics, [collision cross-section $\sigma$]

Tau $\Tau, \tau$

• In mechanics, [torque $\tau$](../167

4): It is also commonly written as $N$.

• Used as a variable for time, instead of $t$.
• Twice the number pi $\tau = 2\pi$

Upsilon $\Upsilon, \upsilon, \varUpsilon$

Upsilon is pronounced as “upsilon”. The TeX codes are \Upsilon, \upsilon, \varUpsilon respectively.

• In particle physics, an upsilon meson $\varUpsilon$

Chi $\Chi, \chi$

Chi is pronounced as “chi”. Teachers advise not to write $x$ as $\chi$ because it is actually chi $x$, not “x” $\chi$. Please do not write it like this. The TeX codes are \Chi, \chi respectively.

• Characteristic function $\chi$

Psi $\Psi, \psi$

Psi is pronounced as “psi”. The TeX codes are \Psi, \psi respectively.

Along with $\phi$, it is often used to represent an arbitrary function.

• In quantum mechanics, wave function $\psi$

Phi $\Phi, \phi ,\varphi$

Phi is pronounced as “phi” or “fi”. It seems that in physics, it is often pronounced as “fi”, while in mathematics, it is pronounced as “phi”. The TeX codes are \Phi, \phi, \varphi respectively.

Along with $\psi$, it is often used to represent an arbitrary function.

• Variable in cylindrical coordinates $\phi$](../1795)
• Variable in spherical coordinates $\phi$](../152)
• In quantum mechanics, wave function $\phi$

Omega $\Omega, \omega$

Omega is pronounced as “omega”. The TeX codes are Omega, omega respectively.

It is the last letter of the Greek alphabet, and the phrase “alpha and omega” means “the beginning and the end”, “everything”.

• In partial differential equations, functional analysis, an open set $\Omega$: It is commonly used notation along with $U$.
• In physics, the unit of resistance $\Omega$
• Solid angle of a sphere $\Omega$
• In physics, angular frequency $\omega$
• Variable for the Fourier transform of $t$ $\omega$
• Complex roots of a polynomial $\omega$