Ṯāʾ
Ṯāʾ (ث) is one of the six letters the Arabic alphabet added to the 22 from the Phoenician alphabet. The others are ḫāʾ, ḏāl, ḍād, ẓāʾ and ġayn). In Modern Standard Arabic, it stands for the voiceless dental fricative [θ], also found in English as the "th" in words such as "thank" and "thin". In Persian, Urdu and Kurdish, it is pronounced as "s" as in "sister" in English.