The letter "ث" is the third letter of the Arabic alphabet. It is pronounced as "th" in English, similar to the "th" in the word "think." In Arabic, "ث" is a voiceless dental fricative, which means it is produced by placing the tongue against the upper teeth. In terms of its shape, "ث" has a distinct three dots placed above it. This letter can appear in different forms depending on its position in a word: initial, medial, or final. It is used in various Arabic words, including ثعلب (fox) and ثلاثة (three).