Tanween refers to the grammatical feature in the Arabic language that indicates the presence of an indefinite noun. It is represented by the addition of two short vowels, typically pronounced as "an," "in," or "un," at the end of a word. This feature helps convey that the noun is not specific, similar to the English articles "a" or "an." In written Arabic, tanween is often marked by diacritical signs, such as the double fatha ( ً ), double kasra ( ٍ ), or double damma ( ٌ ). These markings are essential for proper pronunciation and understanding of the sentence structure, especially in formal contexts like Quranic recitation.