It occurs in the Azerbaijani, Gagauz, Turkish, and Turkmen alphabets.
It commonly represents /ʃ/, the voiceless postalveolar fricative (like sh in shoe).
It is written as the letter S with a cedilla below and it has both the lower-case (U+015F) and the upper-case variants (U+15E).
It is also not present in the Windows 1250 (Central Europe) code page.
The letter was only added to the standard in Unicode 3.0, and some texts in Romanian still use Ş instead.