S

.sa
The Internet country code top-level domain (ccTLD) for Saudi Arabia (Al Arabiyah as Sa'udiyah)

.sb
The Internet country code top-level domain (ccTLD) for Solomon Islands

.sc
The Internet country code top-level domain (ccTLD) for Seychelles

.sd
The Internet country code top-level domain (ccTLD) for Sudan

.se
The Internet country code top-level domain (ccTLD) for Sweden (Sverige)

.sg
The Internet country code top-level domain (ccTLD) for Singapore

.sh
The Internet country code top-level domain (ccTLD) for Saint Helena

.si
The Internet country code top-level domain (ccTLD) for Slovenia (Slovenija)

.sj
The Internet country code top-level domain (ccTLD) for Svalbard and Jan Mayen Islands

.sk
The Internet country code top-level domain (ccTLD) for Slovakia (Slovak Republic, Slovensko)

.sl
The Internet country code top-level domain (ccTLD) for Sierra Leone

.sm
The Internet country code top-level domain (ccTLD) for San Marino

.sn
The Internet country code top-level domain (ccTLD) for Senegal (Sénégal)

.so
The Internet country code top-level domain (ccTLD) for Somalia (Somaliya)

.sr
The Internet country code top-level domain (ccTLD) for Suriname

.st
The Internet country code top-level domain (ccTLD) for São Tomé and Príncipe

.su
The Internet country code top-level domain (ccTLD) for Soviet Union (former, USSR, SSSR)

.sv
The Internet country code top-level domain (ccTLD) for El Salvador

.sw
The Internet country code top-level domain (ccTLD) for Swaziland

.sy
The Internet country code top-level domain (ccTLD) for Syria (Syrian Arab Republic, Souriya)

Second-level domain (SLD)
A domain that is directly below a top-level domain. For example, in www.idnchars.com, idnchars is the second-level domain of the .com TLD. Second-level domains commonly refer to the organization that registered the domain name with a domain name registrar.