<s>
An	O
architecture	B-Architecture
domain	I-Architecture
in	O
enterprise	O
architecture	O
is	O
a	O
broad	O
view	B-Architecture
of	O
an	O
enterprise	O
or	O
system	O
.	O
</s>
<s>
Business	B-Architecture
,	O
data	B-General_Concept
,	O
application	B-Architecture
and	O
technology	B-Architecture
architectures	O
are	O
recognized	O
as	O
the	O
core	O
domains	O
in	O
the	O
most	O
of	O
proposed	O
concepts	O
concerned	O
with	O
the	O
definition	O
of	O
enterprise	O
architecture	O
.	O
</s>
<s>
Since	O
Stephen	O
Spewak	O
's	O
book	O
called	O
enterprise	B-Architecture
architecture	I-Architecture
planning	I-Architecture
(	O
EAP	O
)	O
in	O
1993	O
,	O
and	O
perhaps	O
before	O
then	O
,	O
it	O
has	O
been	O
normal	O
to	O
recognise	O
four	O
types	O
of	O
architecture	B-Architecture
domain	I-Architecture
.	O
</s>
<s>
The	O
British	O
Computer	O
Society	O
's	O
"	O
Reference	O
Model	O
for	O
Enterprise	O
and	O
Solution	B-Architecture
Architecture	I-Architecture
"	O
also	O
follows	O
this	O
subdivision	O
but	O
additionally	O
mentions	O
the	O
(	O
single	O
)	O
application	B-Architecture
architecture	I-Architecture
level	O
just	O
below	O
the	O
applications	B-Architecture
architecture	I-Architecture
as	O
well	O
as	O
the	O
domains	O
of	O
information	O
architecture	O
,	O
information	O
systems	O
architecture	O
,	O
or	O
security	O
architecture	O
(	O
a	O
cross-cutting	O
concern	O
)	O
:	O
</s>
<s>
Business	B-Architecture
architecture	I-Architecture
:	O
The	O
structure	O
and	O
behaviour	O
of	O
a	O
business	B-Architecture
system	O
(	O
not	O
necessarily	O
related	O
to	O
computers	O
)	O
.	O
</s>
<s>
Covers	O
business	B-Architecture
goals	O
,	O
business	B-Architecture
functions	O
or	O
capabilities	O
,	O
business	B-Architecture
processes	O
and	O
roles	O
etc	O
.	O
</s>
<s>
Business	B-Architecture
functions	O
and	O
business	B-Architecture
processes	O
are	O
often	O
mapped	O
to	O
the	O
applications	O
and	O
data	B-General_Concept
they	O
need	O
.	O
</s>
<s>
Data	B-General_Concept
architecture	I-General_Concept
:	O
The	O
data	B-General_Concept
structures	O
used	O
by	O
a	O
business	B-Architecture
and/or	O
its	O
applications	O
.	O
</s>
<s>
Descriptions	O
of	O
data	B-General_Concept
in	O
storage	O
and	O
data	B-General_Concept
in	O
motion	O
.	O
</s>
<s>
Descriptions	O
of	O
data	B-General_Concept
stores	O
,	O
data	B-General_Concept
groups	O
and	O
data	B-General_Concept
items	O
.	O
</s>
<s>
Mappings	O
of	O
those	O
data	B-General_Concept
artifacts	O
to	O
data	B-General_Concept
qualities	O
,	O
applications	O
,	O
locations	O
etc	O
.	O
</s>
<s>
Applications	B-Architecture
architecture	I-Architecture
:	O
The	O
structure	O
and	O
behaviour	O
of	O
applications	O
used	O
in	O
a	O
business	B-Architecture
,	O
focused	O
on	O
how	O
they	O
interact	O
with	O
each	O
other	O
and	O
with	O
users	O
.	O
</s>
<s>
Focused	O
on	O
the	O
data	B-General_Concept
consumed	O
and	O
produced	O
by	O
applications	O
rather	O
than	O
their	O
internal	O
structure	O
.	O
</s>
<s>
In	O
application	B-Architecture
portfolio	O
management	O
,	O
the	O
applications	O
are	O
usually	O
mapped	O
to	O
business	B-Architecture
functions	O
and	O
to	O
application	B-Architecture
platform	O
technologies	O
.	O
</s>
<s>
Application	B-Architecture
(	O
or	O
Component	O
)	O
architecture	O
:	O
The	O
internal	O
structure	O
,	O
the	O
modularisation	O
of	O
software	O
,	O
within	O
an	O
application	B-Architecture
.	O
</s>
<s>
This	O
is	O
software	B-Architecture
architecture	I-Architecture
at	O
the	O
lowest	O
level	O
of	O
granularity	O
.	O
</s>
<s>
It	O
is	O
usually	O
below	O
the	O
level	O
of	O
modularisation	O
that	O
solution	B-Architecture
architects	I-Architecture
define	O
.	O
</s>
<s>
Technology	B-Architecture
architecture	I-Architecture
or	O
infrastructure	O
architecture	O
:	O
The	O
structure	O
and	O
behaviour	O
of	O
the	O
IT	B-Application
infrastructure	I-Application
.	O
</s>
<s>
Note	O
that	O
the	O
applications	B-Architecture
architecture	I-Architecture
is	O
about	O
the	O
application	B-Architecture
portfolio	O
,	O
not	O
the	O
internal	O
architecture	O
of	O
a	O
single	O
application	B-Architecture
-	O
which	O
is	O
often	O
called	O
the	O
application	B-Architecture
architecture	I-Architecture
.	O
</s>
<s>
Many	O
EA	B-Library
frameworks	I-Library
combine	O
data	B-General_Concept
and	O
application	B-Architecture
domains	O
into	O
a	O
single	O
layer	O
,	O
sitting	O
below	O
the	O
business	B-Architecture
(	O
usually	O
a	O
human	O
activity	O
system	O
;	O
that	O
is	O
a	O
notational	O
system	O
expressing	O
a	O
purposeful	O
human	O
activity	O
in	O
a	O
theoretical	O
way	O
using	O
intellectual	O
constructs	O
and	O
not	O
descriptions	O
of	O
actual	O
real-world	O
activity	O
)	O
and	O
above	O
the	O
technology	B-Architecture
(	O
the	O
platform	O
IT	B-Application
infrastructure	I-Application
)	O
.	O
</s>
