word | | Country name |
| form | Senegal | conventional long form: Republic of Senegal conventional short form: Senegal local long form: Republique du Senegal local short form: Senegal former: Senegambia (along with The Gambia), Mali Federation |
| form | Serbia | conventional long form: Republic of Serbia conventional short form: Serbia local long form: Republika Srbija local short form: Srbija former: People's Republic of Serbia, Socialist Republic of Serbia |
| form | Seychelles | conventional long form: Republic of Seychelles conventional short form: Seychelles local long form: Republic of Seychelles local short form: Seychelles |
| form | Sierra Leone | conventional long form: Republic of Sierra Leone conventional short form: Sierra Leone local long form: Republic of Sierra Leone local short form: Sierra Leone |
| form | Singapore | conventional long form: Republic of Singapore conventional short form: Singapore local long form: Republic of Singapore local short form: Singapore |
| form | Sint Maarten | Dutch long form: Land Sint Maarten Dutch short form: Sint Maarten English long form: Country of Sint Maarten English short form: Sint Maarten former: Netherlands Antilles; Curacao and Dependencies |
| form | Slovakia | conventional long form: Slovak Republic conventional short form: Slovakia local long form: Slovenska Republika local short form: Slovensko |
| form | Slovenia | conventional long form: Republic of Slovenia conventional short form: Slovenia local long form: Republika Slovenija local short form: Slovenija former: People's Republic of Slovenia, Socialist Republic of Slovenia |
| form | Solomon Islands | conventional long form: none conventional short form: Solomon Islands local long form: none local short form: Solomon Islands former: British Solomon Islands |