epsilon
(
uppercase
ε
,
lowercase
ε
or
lunate
ϵ
;
greek
:
έψιλον
)
is
the
fifth
letter
of
the
greek
alphabet
,
corresponding
phonetically
to
a
close-mid
front
unrounded
vowel
/e/.
in
the
system
of
greek
numerals
it
has
the
value
five.
it
was
derived
from
the
phoenician
letter
he
he.
letters
that
arose
from
epsilon
include
the
roman
e
and
cyrillic
е.
the
name
"
epsilon
"
(
ἒ
ψιλόν
,
"
simple
e
"
)
was
coined
in
the
middle
ages
to
distinguish
the
letter
from
the
digraph
αι
,
a
former
diphthong
that
had
come
to
be
pronounced
the
same
as
epsilon.
in
essence
,
the
uppercase
form
of
epsilon
looks
identical
to
latin
e.
the
lowercase
version
has
two
typographical
variants
,
both
inherited
from
medieval
greek
handwriting.
one
,
the
most
common
in
modern
typography
and
inherited
from
medieval
minuscule
,
looks
like
a
reversed
"
##number##
"
.
the
other
,
also
known
as
lunate
or
uncial
epsilon
and
inherited
from
earlier
uncial
writing
,
[
##number##
]
[
##number##
]
looks
like
a
semicircle
crossed
by
a
horizontal
bar.
while
in
normal
typography
these
are
just
alternative
font
variants
,
they
may
have
different
meanings
as
mathematical
symbols.
computer
systems
therefore
offer
distinct
encodings
for
them.
[
##number##
]
in
unicode
,
the
character
u+03f5
"
greek
lunate
epsilon
symbol
"
(
ϵ
)
is
provided
specifically
for
the
lunate
form.
in
tex
,
\epsilon
(
\epsilon\
!
)
denotes
the
lunate
form
,
while
\varepsilon
(
\varepsilon\
!
)
denotes
the
inverted-3
form.
there
is
also
a
latin
epsilon
or
"
open
e
"
,
which
looks
similar
to
the
greek
lowercase
epsilon.
it
is
encoded
in
unicode
as
u+025b
(
"
latin
small-letter
open
e
"
,
ɛ
)
and
u+0190
(
"
latin
capital-letter
open
e
"
,
ɛ
)
and
is
used
as
an
ipa
phonetic
symbol.
the
lunate
or
uncial
epsilon
has
also
provided
inspiration
for
the
euro
sign
(
€
)
.
the
lunate
epsilon
(
ϵ
)
is
not
to
be
confused
with
the
set
membership
symbol
(
∈
)
;
nor
should
the
latin
uppercase
epsilon
(
ɛ
)
be
confused
with
the
greek
uppercase
sigma
(
σ
)
.psilon
(
uppercase
ε
,
lowercase
ε
or
lunate
ϵ
;
greek
:
έψιλον
)
is
the
fifth
letter
of
the
greek
alphabet
,
corresponding
phonetically
to
a
close-mid
front
unrounded
vowel
/e/.
in
the
system
of
greek
numerals
it
has
the
value
five.
it
was
derived
from
the
phoenician
letter
he
he.
letters
that
arose
from
epsilon
include
the
roman
e
and
cyrillic
е.
the
name
"
epsilon
"
(
ἒ
ψιλόν
,
"
simple
e
"
)
was
coined
in
the
middle
ages
to
distinguish
the
letter
from
the
digraph
αι
,
a
former
diphthong
that
had
come
to
be
pronounced
the
same
as
epsilon.
in
essence
,
the
uppercase
form
of
epsilon
looks
identical
to
latin
e.
the
lowercase
version
has
two
typographical
variants
,
both
inherited
from
medieval
greek
handwriting.
one
,
the
most
common
in
modern
typography
and
inherited
from
medieval
minuscule
,
looks
like
a
reversed
"
##number##
"
.
the
other
,
also
known
as
lunate
or
uncial
epsilon
and
inherited
from
earlier
uncial
writing
,
[
##number##
]
[
##number##
]
looks
like
a
semicircle
crossed
by
a
horizontal
bar.
while
in
normal
typography
these
are
just
alternative
font
variants
,
they
may
have
different
meanings
as
mathematical
symbols.
computer
systems
therefore
offer
distinct
encodings
for
them.
[
##number##
]
in
unicode
,
the
character
u+03f5
"
greek
lunate
epsilon
symbol
"
(
ϵ
)
is
provided
specifically
for
the
lunate
form.
in
tex
,
\epsilon
(
\epsilon\
!
)
denotes
the
lunate
form
,
while
\varepsilon
(
\varepsilon\
!
)
denotes
the
inverted-3
form.
there
is
also
a
latin
epsilon
or
"
open
e
"
,
which
looks
similar
to
the
greek
lowercase
epsilon.
it
is
encoded
in
unicode
as
u+025b
(
"
latin
small-letter
open
e
"
,
ɛ
)
and
u+0190
(
"
latin
capital-letter
open
e
"
,
ɛ
)
and
is
used
as
an
ipa
phonetic
symbol.
the
lunate
or
uncial
epsilon
has
also
provided
inspiration
for
the
euro
sign
(
€
)
.
the
lunate
epsilon
(
ϵ
)
is
not
to
be
confused
with
the
set
membership
symbol
(
∈
)
;
nor
should
the
latin
uppercase
epsilon
(
ɛ
)
be
confused
with
the
greek
uppercase
sigma
(
σ
)
.