The sukun is another diacritical mark in Arabic. Sukun is the Arabic word for silence. It is marked with a small circle above a letter, indicating the absence of a short vowel. Instead, adjoining consonants will be pronounced together. Like the short vowels (fatha, damma, kasra), the sukun is normally not written. The sukun can also come at the end of a word, making a word end in a consonant sound. In these situations, the sukun is less likely to be written, though will be marked at the end of words in fully vowelled texts, such as the Quran.

Examples:

قَلْب (qalb) - heart

غُرْفة (ghurfa) - room

كُرْسي (kursi) - chair

يَيْم (youm) - day