Ś

Ś is a letter of the Latin alphabet, formed from S with the addition of an acute accent. It is used in Silesian, Polish, and Montenegrin alphabets, and in certain other languages or romanizations.

Uses

Slavic languages – usually the palatalized form of /s/
Indo-Aryan: voiceless postalveolar fricative or voiceless [alveolo-palatal fricative]
Ladin language – word-initial
In some dialects of the Emilian language –
transliteration of a palatalized s in the Lydian language
In Proto-Semitic, a reconstructed voiceless [lateral fricative] phoneme, the parent phoneme of Ge'ez Śawt ሠ.
a sibilant phoneme of the earliest phase of the Sumerian language.
transliteration of a letter of the Etruscan alphabet, related to San and Tsade.
a sibilant phoneme of the ancient Iberian language.

The HTML codes are:

The Unicode codepoints are U+015A for Ś and U+015B for ś.