Alpha
In Mathematics
• Often represents
angles in algebra.
• In statistics, the
significance level
when a Normal
Distribution is used.
In Science
• Alpha Radiation
• Angular acceleration
• In Zoology, used to
name dominant
individual in wolf or
dog pack.
Beta
In Science
• Beta Radiation
Gamma
In Mathematics
• 𝛾 = Chromatic Number of a
graph.
• Γ(𝑥) is the Gamma Function.
It allows the factorial function
to be extended to
real/negative/complex
numbers.
• In statistics, the Γ distribution
is the conceptual opposite of
the Multinomial.
• In Computer Science, the tape
alphabet of a Turing Machine.
In Science
• Gamma Radiation in
nuclear physics.
• Heat Capacity Ratio in
thermodynamics.
• Surface Energy in
materials science.
𝜀∈Ε
Epsilon
In Mathematics
• 𝜀 is an arbitrarily small
positive constant.
• ∈ means “is an element
of” in Set Theory.
• In Computer Science,
denotes an empty string.
• In statistics, to refer to
error terms.
In Science
• 𝜀 refers to elasticity in
Economics.
• Electromotive force.
• In Astronomy, the 5th
biggest star in a
constellation.
Zeta
In Mathematics
• 𝜁(𝑥) is the Riemann Zeta
Function.
In Science
• The damping ratio of
an oscillating system.
• Effective nuclear
charge on an electron.
Eta
In Mathematics
• 𝜂(𝑥) is the Dirichlet Eta
Function in number theory.
In Science
• 𝜼-mesons in particle
physics.
• The efficiency of a
power supply.
• In Oceonography, the
measurement of sealevel height above the
mean in that location.
Theta
In Mathematics
• 𝜃 is often used to denote an
angle.
• In probability, 𝜃 often denotes
the likelihood function (i.e.
𝑝 𝑒𝑓𝑓𝑒𝑐𝑡 𝑐𝑎𝑢𝑠𝑒 ).
• One of the Chebyshev
Functions in Prime Number
Theory.
• In Computer Science, “Big
Theta” puts a bound on the
complexity of an algorithm.
In Science
• The potential
temperature in
Meteorology.
• In neuroscience, Brain
Signal Frequency
ranging from 4-8Hz.
Iota
In Mathematics
• Can be used as the value of
−1, but a regular ‘𝑖’ is more
typically used.
Kappa
In Mathematics
• In graph theory, 𝜅 is the
minimum number of edges
that need to be removed
from a graph to make it
‘disconnected’.
• A measurement of ‘inter-rater
reliability’ in surveys, i.e. how
consistent people’s responses
were.
In Science
• In Chemistry, the
compressibility of a
compound.
Lambda
In Mathematics
• Sometimes used to mean the
‘empty set’ in Set Theory,
although ∅ more often used.
• In lambda calculus 𝜆
represents a nameless
function, e.g. 𝜆𝑥. 𝑥 2 means
𝑓 𝑥 = 𝑥2
• An eigenvalue of a matrix.
• Λ is a set of logical axioms in
First Order Logic.
In Science
• The wavelength of any
wave.
• 𝝀 is the half life of a
radioactive material.
Mu
In Mathematics
• 𝜇 indicates the mean in a
Normal Distribution.
• The population mean.
• The Mobius Function in
number theory.
• The Integrating Factor in
differential equations.
• The coefficient of friction in
mechanics.
In Science
• The elementary
particles called the
muon and antimuon.
• The chemical
potential of a system
in thermodynamics.
Nu
In Mathematics
• 𝜈 is the degree of freedom in
statistics.
In Science
• 𝜈 is the frequency of a
wave.
• 𝜈 is the number of
neutrons released per
fission.
• Any of the three kinds
of neutrino in particle
physics.
Xi
In Mathematics
• Eigenvectors.
• The ‘universal set’ in set
theory.
• Often used to denote random
variables in statistics.
In Science
• The correlation
function in astronomy.
• Potential difference in
Physics (in Volts).
Omicron
In Mathematics
• Originally used in ‘Big O’
notation, which describes
how a function asymptotically
grows, although a normal ‘O’
is preferred.
In Science
• The 13th biggest star
in a constellation
group.
Pi
In Mathematics
• 𝜋 = 3.1412 …
The ratio between the diameter and
circumference of a circle.
• Π is the product of expressions,
e.g. 3𝑖=1 𝑖 2 = 12 × 22 × 32
• The 𝜋 𝑥 ‘prime counting function’ is
the number of primes numbers up to
a given integer 𝑥.
Rho
In Mathematics
• Various densities (e.g.
𝑚𝑎𝑠𝑠/𝑣𝑜𝑙𝑢𝑚𝑒)
• A plastic number (a unique
real solution to 𝑥 3 = 𝑥 + 1)
• 𝜌(𝐴) is the spectral radius of
a matrix 𝐴.
• Spearman’s Rank Correlation
Coefficient in statistics.
In Science
• 𝜌 indicates resistivity.
• In molecular biology,
the Rho Protein
responsible for the
termination of RNA
synthesis.
𝜎Σ𝜍
Sigma
In Mathematics
• 𝜎 is the population standard
deviation in statistics, or the
standard deviation of a
Normal Distribution.
• Σ is used to sum expressions.
E.g. 3𝑖=1 𝑖 2 = 12 + 22 + 32
• The covariance matrix in
statistics.
• 𝜎0 (𝑥) finds the sum of the
factors of 𝑥, e.g.
𝜎0 8 = 1 + 2 + 4 + 8
In Science
• 𝝈-receptor in biology.
• 𝜎 used for surface
tension.
• 𝝈-bonds in chemistry.
• A measure of
electrical
conductivity.
Tau
In Mathematics
• 𝜏 is twice as big as 𝜋.
• Torsion of a curve in
differential geometry.
• The tau function in number
theory.
In Science
• Often used in Physics
as a time variable
(particularly if 𝑡 is
already being used for
temperature).
• Torque, the rotational
force in mechanics.
• Tau Protein associated
with diseases such as
Alzheimer’s.
Upsilon
In Science
• Υ is the Upsilon
Particle in particle
physics.
Phi
In Mathematics
1+ 5
•
• 𝜙 = 2 is the Golden Ratio.
• 𝜙(𝑥) is the Probability Density
Function for the Normal
•
Distribution.
• A sentence in First Order Logic.
• 𝜙 𝑛 is Euler’s Totient Function.
It gives the number of values up
to 𝑛 where the greatest common
divisor of that number and 𝑛 is
1. e.g.:
𝜙 6 = 2, because 𝐺𝐶𝐷 1,6 =
6 and 𝐺𝐶𝐷 5,6 = 1
In Science
The aromatic
functional group in
organic chemistry.
Porosity in geology.
Chi
In Mathematics
• The 𝜒 2 (“Chi Squared”)
distribution in statistics,
frequently used in hypothesis
testing.
• In topology, the Euler
characteristic of a surface.
In Science
• In chemistry, the mole
fraction and
electronegativity.
• The optic chiasm in
neurology (due to its
shape resembling the
letter)
Psi
In Mathematics
• The sum of the reciprocals of
the Fibonacci numbers:
1 1 1 1 1
𝜓= + + + + +⋯
1 1 2 3 5
• The Polygamma Function.
In Science
• Used to represent
wave functions in
quantum mechanics.
• Water Potential in
movement of water
between plant cells.
• The 𝚿-meson in
particle physics.
• In astronomy, the
planet Neptune.
Omega
In Mathematics
• In statistics, Ω used to indicate
the sample space, i.e. the set of
possible outcomes.
• Ω is the Omega Constant, a
solution of the Lambert-W
function.
• The omega subgroups in group
theory.
• 𝜔 are the complex cube roots
of 1.
• 𝜔 𝑛 is the number of distinct
factors of 𝑛. e.g. 𝜔 6 = 4
In Science
• Ω is the unit of
electrical resistance.
• Ω-baryons in particle
physics.
• 𝜔 is angular velocity.
• 𝜔 is the ranking of a
star’s brightness
within a constellation.