ㅆ

Etymology
Doubled ㅅ (siot)

Letter

 * 1) A digraph of hangul, the Korean alphabet.
 * In North Korea, ㅆ is called 된시읏 (doensieut), "strong ㅅ (sieut)". In South Korea, it is called 쌍시옷 (ssangsiot), "doubled ㅅ (siot)".
 * ㅆ is pronounced as a sibilant with tense phonation (IPA: [s͈] or [z̬]), i.e. similar to the English s, but with a stiff tongue and glottal opening.

Usage notes
In Dongguk Jeong'un (東國正韻), this letter was used to transcribe voiced alveolar fricative ([z]) of Middle Chinese.