The letter "ص" is the sixteenth letter of the Arabic alphabet. It is pronounced as "ṣād" and represents a voiceless emphatic alveolar fricative sound. In Arabic script, it is written in different forms depending on its position in a word: isolated, initial, medial, and final. In terms of numerical value, "ص" corresponds to the number 90 in the Arabic numeral system. It is commonly used in various Arabic words, including صديق (friend) and صباح (morning). The letter is also significant in Islamic texts, where it appears in many important terms.