# Physics Study Guide/Greek alphabet

# About the *Common uses in Physics*

While these are indeed common usages, it should be pointed out that
there are many other usages and that other letters are used for the same
purpose. The reason is quite simple: there are only so many symbols in
the Greek and Latin alphabets, and scientists and mathematicians
generally do not use symbols from other languages. It is a common trap
to associate a symbol exclusively with some particular meaning, rather
than learning and understanding the physics and relations behind it.

+------------------+------------------+---------+------------------+
| Capital          | Lower case       | Name    | Common use in    |
|                  |                  |         | Physics          |
+==================+==================+=========+==================+
| ```{=mediawiki}  | ```{=mediawiki}  | alpha   | Angular          |
| {{math|          | {{math|          |         | acceleration\    |
| size=1.5em|<math | size=1.5em|<math |         | Linear           |
| >\Alpha</math>}} | >\alpha</math>}} |         | expansion\       |
| ```              | ```              |         | Coefficient\     |
|                  |                  |         | Alpha particle   |
|                  |                  |         | (helium          |
|                  |                  |         | nucleus)\        |
|                  |                  |         | Fine Structure   |
|                  |                  |         | Constant         |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | beta    | Beta particle    |
| {{math           | {{math           |         | --- high energy  |
| |size=1.5em|<mat | |size=1.5em|<mat |         | electron\        |
| h>\Beta</math>}} | h>\beta</math>}} |         | Sound intensity  |
| ```              | ```              |         |                  |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | gamma   | Gamma ray (high  |
| {{math|          | {{math|          |         | energy EM wave)\ |
| size=1.5em|<math | size=1.5em|<math |         | Ratio of heat    |
| >\Gamma</math>}} | >\gamma</math>}} |         | capacities (in   |
| ```              | ```              |         | an ideal gas)\   |
|                  |                  |         | Relativistic     |
|                  |                  |         | correction       |
|                  |                  |         | factor Shear     |
|                  |                  |         | strain           |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | delta   | Δ=\"Change in\"\ |
| {{math|          | {{math|          |         | δ                |
| size=1.5em|<math | size=1.5em|<math |         | =\"Infinitesimal |
| >\Delta</math>}} | >\delta</math>}} |         | change in (),    |
| ```              | ```              |         | also used to     |
|                  |                  |         | denote the Dirac |
|                  |                  |         | delta function   |
|                  |                  |         | (reference       |
|                  |                  |         | needed)\"        |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | epsilon | Emissivity\      |
| {{math|si        | {{math|si        |         | Strain (Direct   |
| ze=1.5em|<math>\ | ze=1.5em|<math>\ |         | e.g. tensile or  |
| Epsilon</math>}} | epsilon</math>}} |         | compression)\    |
| ```              | ```              |         | Permittivity\    |
|                  |                  |         | EMF              |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | zeta    | (no common use)  |
| {{math           | {{math           |         |                  |
| |size=1.5em|<mat | |size=1.5em|<mat |         |                  |
| h>\Zeta</math>}} | h>\zeta</math>}} |         |                  |
| ```              | ```              |         |                  |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | eta     | Viscosity\       |
| {{mat            | {{mat            |         | Energy           |
| h|size=1.5em|<ma | h|size=1.5em|<ma |         | efficiency       |
| th>\Eta</math>}} | th>\eta</math>}} |         |                  |
| ```              | ```              |         |                  |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | theta   | Angle (°, rad)\  |
| {{math|          | {{math|          |         | Temperature      |
| size=1.5em|<math | size=1.5em|<math |         |                  |
| >\Theta</math>}} | >\theta</math>}} |         |                  |
| ```              | ```              |         |                  |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | iota    | The lower case   |
| {{math           | {{math           |         | $\iota\;$ is     |
| |size=1.5em|<mat | |size=1.5em|<mat |         | rarely used,     |
| h>\Iota</math>}} | h>\iota</math>}} |         | while $\Iota$ is |
| ```              | ```              |         | sometimes used   |
|                  |                  |         | for the identity |
|                  |                  |         | matrix or the    |
|                  |                  |         | moment of        |
|                  |                  |         | inertia. Note    |
|                  |                  |         | that $\iota$ is  |
|                  |                  |         | not to be        |
|                  |                  |         | confused with    |
|                  |                  |         | the Roman        |
|                  |                  |         | character $i$    |
|                  |                  |         | (which has a dot |
|                  |                  |         | and is much more |
|                  |                  |         | widely used in   |
|                  |                  |         | mathematics and  |
|                  |                  |         | physics).        |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | kappa   | Spring constant\ |
| {{math|          | {{math|          |         | Dielectric       |
| size=1.5em|<math | size=1.5em|<math |         | constant         |
| >\Kappa</math>}} | >\kappa</math>}} |         |                  |
| ```              | ```              |         |                  |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | lambda  | Wavelength\      |
| {{math|s         | {{math|s         |         | Thermal          |
| ize=1.5em|<math> | ize=1.5em|<math> |         | conductivity\    |
| \Lambda</math>}} | \lambda</math>}} |         | Constant\        |
| ```              | ```              |         | Eigenvalue of a  |
|                  |                  |         | matrix\          |
|                  |                  |         | Linear density   |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | mu      | Coefficient of   |
| {{ma             | {{ma             |         | friction\        |
| th|size=1.5em|<m | th|size=1.5em|<m |         | Electrical       |
| ath>\Mu</math>}} | ath>\mu</math>}} |         | mobility\        |
| ```              | ```              |         | Reduced mass\    |
|                  |                  |         | Permeability     |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | nu      | Frequency        |
| {{ma             | {{ma             |         |                  |
| th|size=1.5em|<m | th|size=1.5em|<m |         |                  |
| ath>\Nu</math>}} | ath>\nu</math>}} |         |                  |
| ```              | ```              |         |                  |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | xi      | Damping          |
| {{ma             | {{ma             |         | cofficient       |
| th|size=1.5em|<m | th|size=1.5em|<m |         |                  |
| ath>\Xi</math>}} | ath>\xi</math>}} |         |                  |
| ```              | ```              |         |                  |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | omicron | (no common use)  |
| {{math|si        | {{math|si        |         |                  |
| ze=1.5em|<math>\ | ze=1.5em|<math>\ |         |                  |
| Omicron</math>}} | omicron</math>}} |         |                  |
| ```              | ```              |         |                  |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | pi      | Product symbol   |
| {{ma             | {{ma             |         | $\Pi$\           |
| th|size=1.5em|<m | th|size=1.5em|<m |         | Circle number    |
| ath>\Pi</math>}} | ath>\pi</math>}} |         | $                |
| ```              | ```              |         | \pi:=3.14159...$ |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | rho     | Volume density\  |
| {{mat            | {{mat            |         | Resistivity      |
| h|size=1.5em|<ma | h|size=1.5em|<ma |         |                  |
| th>\Rho</math>}} | th>\rho</math>}} |         |                  |
| ```              | ```              |         |                  |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | sigma   | Sum symbol\      |
| {{math|          | {{math|          |         | Boltzmann        |
| size=1.5em|<math | size=1.5em|<math |         | constant\        |
| >\Sigma</math>}} | >\sigma</math>}} |         | Electrical       |
| ```              | ```              |         | conductivity\    |
|                  |                  |         | Uncertainty\     |
|                  |                  |         | Stress (Direct   |
|                  |                  |         | e.g. tensile,    |
|                  |                  |         | compression)\    |
|                  |                  |         | Surface density  |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | tau     | Torque\          |
| {{mat            | {{mat            |         | Tau particle (a  |
| h|size=1.5em|<ma | h|size=1.5em|<ma |         | lepton)\         |
| th>\Tau</math>}} | th>\tau</math>}} |         | Time constant    |
| ```              | ```              |         | Shear stress     |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | upsilon | mass to light    |
| {{math|si        | {{math|si        |         | ratio            |
| ze=1.5em|<math>\ | ze=1.5em|<math>\ |         |                  |
| Upsilon</math>}} | upsilon</math>}} |         |                  |
| ```              | ```              |         |                  |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | phi     | M                |
| {{mat            | {{mat            |         | agnetic/electric |
| h|size=1.5em|<ma | h|size=1.5em|<ma |         | flux\            |
| th>\Phi</math>}} | th>\phi</math>}} |         | Angle (°, rad)   |
| ```              | ```              |         |                  |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | chi     | Rabi frequency   |
| {{mat            | {{mat            |         | (lasers)\        |
| h|size=1.5em|<ma | h|size=1.5em|<ma |         | Susceptibility   |
| th>\Chi</math>}} | th>\chi</math>}} |         |                  |
| ```              | ```              |         |                  |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | psi     | Wave function    |
| {{mat            | {{mat            |         |                  |
| h|size=1.5em|<ma | h|size=1.5em|<ma |         |                  |
| th>\Psi</math>}} | th>\psi</math>}} |         |                  |
| ```              | ```              |         |                  |
+------------------+------------------+---------+------------------+
| ```{=mediawiki}  | ```{=mediawiki}  | omega   | Ohms (unit of    |
| {{math|          | {{math|          |         | electrical       |
| size=1.5em|<math | size=1.5em|<math |         | resistance)\     |
| >\Omega</math>}} | >\omega</math>}} |         | ω Angular        |
| ```              | ```              |         | velocity         |
+------------------+------------------+---------+------------------+

: **Greek Alphabet**

# See Also

Greek alphabet on
Wikipedia

Greek letters used in mathematics, science, and
engineering

