The "kasra" is a diacritical mark used in the Arabic script. It appears as a small diagonal line placed below a letter, indicating a short vowel sound, specifically the vowel "i." This mark helps in the correct pronunciation of words, as Arabic is a language that relies heavily on these diacritics for clarity. In addition to the kasra, Arabic has other diacritical marks, such as the "fatha" and "damma," which represent different vowel sounds. Understanding the kasra is essential for reading and writing in Arabic, as it contributes to the overall meaning of words and sentences in the language.