<s>
A	O
country	B-Protocol
code	I-Protocol
second-level	I-Protocol
domain	I-Protocol
is	O
a	O
second-level	B-Protocol
domain	I-Protocol
to	O
a	O
country	B-Application
code	I-Application
top-level	I-Application
domain	I-Application
.	O
</s>
<s>
Such	O
a	O
domain	O
may	O
be	O
reserved	O
by	O
a	O
domain	B-Protocol
name	I-Protocol
registry	I-Protocol
for	O
the	O
registration	O
of	O
third-level	B-Protocol
domains	I-Protocol
,	O
or	O
assigned	O
to	O
a	O
third	O
party	O
as	O
a	O
subdomain	B-Protocol
.	O
</s>
<s>
Many	O
country	B-Application
code	I-Application
domain	I-Application
registries	O
implement	O
domain	O
name	O
classes	O
at	O
the	O
second	O
level	O
underneath	O
their	O
ccTLD	B-Application
,	O
such	O
as	O
are	O
present	O
in	O
the	O
original	O
generic	O
top-level	O
domains	O
,	O
,	O
and	O
,	O
which	O
were	O
intended	O
for	O
commercial	O
entities	O
,	O
network	O
operators	O
,	O
and	O
non-profit	O
organizations	O
,	O
respectively	O
.	O
</s>
<s>
For	O
example	O
,	O
the	O
United	O
Kingdom	O
(	O
.uk	B-Application
)	O
uses	O
for	O
commercial	O
purposes	O
and	O
for	O
academic	O
registrants	O
.	O
</s>
<s>
Brazil	O
(	O
.br	O
)	O
has	O
a	O
high	O
number	O
of	O
predefined	O
second-level	B-Protocol
domains	I-Protocol
,	O
140	O
as	O
of	O
2021	O
;	O
they	O
range	O
from	O
for	O
commercial	O
activities	O
and	O
for	O
veterinarians	O
to	O
for	O
wikis	O
(	O
see	O
.br	O
§	O
Second-level	B-Protocol
domains	I-Protocol
)	O
.	O
</s>
