ʂ

ʂ U+0282, ʂ LATIN SMALL LETTER S WITH HOOK ← ʁ [U+0281] IPA Extensions ʃ → [U+0283]

Character variations

ᶳ U+1DB3, ᶳ MODIFIER LETTER SMALL S WITH HOOK ← ᶲ [U+1DB2] Phonetic Extensions Supplement ᶴ → [U+1DB4]

English Wikipedia has an article on:

voiceless retroflex fricative

Wikipedia

• IPA:

  (file)

ʂ

1. (IPA) a voiceless retroflex sibilant.
2. (superscript ⟨ᶳ⟩, IPA) [ʂ]-fricated release of a plosive (e.g. [tᶳ] or [ʈᶳ]), sometimes implying an affricate (e.g. ⟨ʈᶳ⟩ for [ʈ͡ʂ]); [ʂ]-coloring; or a weak, fleeting or epenthetic [ʂ].

• ʐ (“voiced retroflex fricative”)

• (Latin script):  Aa  Bb  Cc  Dd  Ee  Ff  Gg  Hh  Ii  Jj  Kk  Ll  Mm  Nn  Oo  Pp  Qq  Rr  Sſs  Tt  Uu  Vv  Ww  Xx  Yy  Zz
• (Variations of letter S):  Śś  Ṥṥ  Ŝŝ  Šš  Ṧṧ  Ṡṡẛ  Şş  Ṣṣ  Ṩṩ  Șș  S̩s̩  ᵴ  ᶊ  ʂ  ȿ  ꜱ  Ｓｓ  ſ  ẞß  stſt
• (Letters with hook):  Ảả  Ẳẳ  Ẩẩ  Ɓɓ  Ƈƈ  Ɗɗ  ᶑ  Ẻẻ  Ƒƒ  Ɠɠ  ɦ  Ỉỉ  Ƙƙ  ᶆ  Ɱɱ  Ỏỏ  Ởở  Ƥƥ  ʠ  Ƭƭ  Ủủ  Ửử  Ʋʋ  Ⱳⱳ  Ƴƴ  Ỷỷ

ʂ (upper case Ʂ)

1. (obsolete) A letter of the draft Pinyin alphabet of the 1950s; used to represent /ʂ/ and corresponds to modern ⟨sh⟩.