Other hyponyms of letter of the alphabet include
ascender,
descender,
digram,
digraph,
initial,
A,
a,
B,
b,
C,
c,
D,
d,
E,
e,
F,
f,
G,
g,
H,
h,
I,
i,
J,
j,
K,
k,
L,
l,
M,
m,
N,
n,
O,
o,
P,
p,
Q,
q,
R,
r,
S,
s,
T,
t,
U,
u,
V,
v,
double-u,
W,
w,
ex,
X,
x,
wye,
Y,
y,
izzard,
Z,
z,
zed,
zee,
alpha,
beta,
gamma,
delta,
epsilon,
zeta,
eta,
theta,
iota,
kappa,
lambda,
mu,
nu,
xi,
omicron,
pi,
rho,
sigma,
tau,
upsilon,
phi,
chi,
khi,
psi,
omega,
aleph,
beth,
gimel,
daleth,
he,
waw,
zayin,
heth,
teth,
yodh,
kaph,
lamedh,
mem,
nun,
samekh,
ayin,
pe,
sadhe,
qoph,
resh,
sin,
shin,
taw,
polyphone,
polyphonic letter,
block capital,
block letter,
vowel,
consonant,
yus.