Alphabets - a MaS Tutor.

The Latin
Name	Upper Case	Examples of Use	Lower Case	Examples of Use
ay	$A$	area, atomic number, nucleon number	$a$	First term in an arithmetic sequence
bee	$B$	B-field, Buoyancy, eleven in hexidecimal	$b$	Bottom Quark
cee	$C$	coulomb, the unit of electrical charge	$c$	the $y$ -intercept.
dee	$D$	deuterium	$d$	distance
ee	$E$	Youngs Modulus	$e$	the natural base
ef	$F$	Force	$f$	frequency
gee	$G$	Giga, Universal Gravitation Constant	$g$	graviational field strength, gram
aitch	$H$	-	$h$	height
i	$I$	electrical current; impulse	$i$	the imaginary number, $i = \sqrt{-1}$
jay	$J$	unit of energy, joule	$j$	unit vector in the direction of the y-axis
kay	$K$	Kelvin the unit of absolute temperature	$k$	a constant
el	$L$	length;	$l$	length
em	$M$	moments, mega	$m$	mass
en	$N$	number of particles	$n$	number of moles, number density
o	$O$	the origin of the cartesian plan, the error function	$o$	-
pee	$P$	power, pressure, phosphorus	$p$	pressure, momentum
cue	$Q$	a collection of charge	$q$	the charge on a particle
ar	$R$	gas constant	$r$	radius
ess	$S$	sum of terms in a sequence	$s$	displacement
tee	$T$	time period	$t$	time
u	$U$	internal energy	$u$	initial velocity
vee	$V$	volume, volt, potential difference	$v$	velocity, final velocity
double-u	$W$	weight; unit for power, watt.	$w$	width
ex	$X$	a random variable	$x$	first dimension, the unknown.
wye	$Y$	Yttrium	$y$	second dimension.
zed	$Z$	Acoustic Impedence.	$z$	third dimension.

For more see Latin Letters Used in Mathematics, Science, and Engineering

The Greek
Name	Upper Case	Examples of Use	Lower Case	Examples of Use
alpha	$Α$	See Latin A	$α$	Symbol for alpha radiation; An angle.
beta	$Β$	See Latin B	$β$	Symbol for beta radiation.
gamma	$Γ$	-	$γ$	Symbol for gamma radiation, or the photon.
delta	$Δ$	A change; the Discriminant $(b^{2} - 4 a c)$ in quadratics.	$δ$	A small change
epsilon	$Ε$	See Latin E	$ε$	On it's own the relative permittivity (sometimes with a subscript of "r", $ε_{r}$ ); it's the permittivity of free space when with a zero subscript, $ε_{0}$ ; Mechanical strain .
zeta	$Ζ$	See Latin Z	$ζ$	-
eta	$Η$	See Latin H	$η$	Viscosity.
theta	$Θ$	-	$θ$	An angle; A change in temperature (usually preceded by a $Δ$ ).
Iota	$Ι$	See Latin I	$ι$	-
kappa	$Κ$	See Latin K	$κ$	-
lambda	$Λ$	$Λ^{0}$ the lambda baryon	$λ$	Wavelength; Probability of decay in a given time frame
mu	$Μ$	See Latin M	$μ$	Coefficient of Fraction; $10^{-6}$ ; symbol for the muon, $μ^{\pm}$ .
nu	$Ν$	See Latin N	$ν$	-
xi	$Ξ$	-	$ξ$	the universal set.
omicron	$Ο$	See Latin O	$ο$	See Latin o
pi	$Π$	Product of factors, $Π_{i = 1}^{n}$	$π$	Almost exclusively, used for the ratio of $\frac{circumference}{diameter}$ ; Pion.
rho	$Ρ$	See Latin P	$ρ$	Density; Resistivity
sigma	$Σ$	Sum of terms, $Σ_{i = 1}^{n}$	$σ$	Stress ; Standard Deviation
tau	$Τ$	See Latin T	$τ$	torque; Symbol for the tauon
upsilon	$Υ$	-	$υ$	See Latin v
phi	$Φ$	Magnet Flux Linkage	$φ$ , $ϕ$	Magnetic Flux
chi	$Χ$	See Latin X	$χ$	-
psi	$Ψ$	-	$ψ$	-
omega	$Ω$	Ohm, unit of electrical resistance	$ω$	Angular speed/frequency

For a more complete list see Greek letters and Latin letters used in mathematics, science, and engineering.
(Care of en.wikipedia.org)

Note: ^[1] These symbols are used, but as they are easily confused with the Latin alphabet symbol. The information on these letters can be found in the Latin alphabet list.

The Latin

The Greek