Most, if not all, countries, have their an abbreviation of the country name in the address of sites hosted in the country. For example, for Australia it is .com.au. Here is a list of those abbreviations for all the countries of the world (and some colonies, too)
Afghanistan AF
Albania AL
Algeria DZ
Andorra AD
Angola AO
Anguilla AI
Antarctica AQ
Antigua and Barbuda AG
Argentina AR
Armenia AM
Aruba AW
Ascension Island AC
Australia AU
Austria AT
Azerbaijan AZ
Bahamas BS
Bahrain BH
Bangladesh BD
Barbados BB
Belarus BY
Belgium BE
Belize BZ
Benin BJ
Bermuda BM
Bhutan BT
Bolivia BO
Bosnia and Herzegovina BA
Botswana BW
Bouvet Island BV
Brazil BR
British Indian Ocean Territory IO
Brunei Darussalam BN
Bulgaria BG
Burkina Faso BF
Burundi BI
Cambodia KH
Cameroon CM
Canada CA
Cap Verde CV
Cayman Islands KY
Central African Republic CF
Chad TD
Chile CL
China CN
Christmas Island CX
Cocos (Keeling) Islands CC
Colombia CO
Comoros KM
Congo, Democratic Republic of CD
Congo, Republic of CG
Cook Islands CK
Costa Rica CR
Cote d’Ivoire (Ivory Coast) CI
Croatia HR
Cuba CU
Cyprus CY
Czech Republic CZ
Denmark DK
Djibouti DJ
Dominica DM
Dominican Republic DO
Timor-Leste (East Timor) TP
Ecuador EC
Egypt EG
El Salvador SV
Equatorial Guinea GQ
Eritrea ER
Estonia EE
Ethiopia ET
Falkland Islands FK
Faroe Islands FO
Fiji FJ
Finland FI
France FR
French Guiana GF
French Polynesia PF
French Southern Territories TF
Gabon GA
Gambia GM
Georgia GE
Germany DE
Ghana GH
Gibraltar GI
Greece GR
Greenland GL
Grenada GD
Guadeloupe GP
Guatemala GT
Guernsey GG
Guinea GN
Guinea-Bissau GW
Guyana GY
Haiti HT
Heard and McDonald Islands HM
Honduras HN
Hong Kong HK
Hungary HU
Iceland IS
India IN
Indonesia ID
Iran IR
Iraq IQ
Ireland IE
Isle of Man IM
Israel IL
Italy IT
Jamaica JM
Japan JP
Jersey JE
Jordan JO
Kazakhstan KZ
Kenya KE
Kiribati KI
Korea (North) KP
Korea (South) KR
Kuwait KW
Kyrgyzstan KG
Laos LA
Latvia LV
Lebanon LB
Lesotho LS
Liberia LR
Libya LY
Liechtenstein LI
Lithuania LT
Luxembourg LU
Macau MO
Macedonia MK
Madagascar MG
Malawi MW
Malaysia MY
Maldives MV
Mali ML
Malta MT
Martinique MQ
Mauritania MR
Mauritius MU
Mayotte YT
Mexico MX
Moldova MD
Monaco MC
Mongolia MN
Montserrat MS
Morocco MA
Mozambique MZ
Myanmar MM
Namibia NA
Nauru NR
Nepal NP
Netherlands NL
Netherlands Antilles AN
New Caledonia NC
New Zealand NZ
Nicaragua NI
Niger NE
Nigeria NG
Niue NU
Norfolk Island NF
Norway NO
Oman OM
Pakistan PK
Palestine PS
Panama PA
Papua New Guinea PG
Paraguay PY
Peru PE
Philippines PH
Pitcairn Island PN
Poland PL
Portugal PT
Qatar QA
Reunion Island RE
Romania RO
Russian Federation RU
Rwanda RW
Saint Kitts and Nevis KN
Saint Lucia LC
Saint Vincent and the Grenadines VC
San Marino SM
Sao Tome and Principe ST
Saudi Arabia SA
Senegal SN
Seychelles SC
Sierra Leone SL
Singapore SG
Slovak Republic SK
Slovenia SI
Solomon Islands SB
Somalia SO
South Africa ZA
South Georgia and the South Sandwich Islands GS
Spain ES
Sri Lanka LK
St. Helena SH
St. Lucia LC
St. Pierre and Miquelon PM
Sudan SD
Suriname SR
Svalbard and Jan Mayen Islands SJ
Swaziland SZ
Sweden SE
Switzerland CH
Syrian Arab Republic SY
Taiwan TW
Tajikistan TJ
Tanzania TZ
Thailand TH
Togo TG
Tokelau TK
Tonga TO
Trinidad and Tobago TT
Tunisia TN
Turkey TR
Turkmenistan TM
Turks and Caicos Islands TC
Tuvalu TV
Uganda UG
Ukraine UA
United Arab Emirates AE
United Kingdom UK
United States US
Uruguay UY
Uzbekistan UZ
Vanuatu VU
Vatican City VA
Venezuela VE
Vietnam VN
Virgin Islands (British) VG
Wallis and Futuna Islands WF
Western Sahara EH
Western Samoa WS
Yemen YE
Yugoslavia YU
Zambia ZM
Zimbabwe ZW
