MOON Arabic qamar قمر
The moon is frequently mentioned in the Qur’an. Muhammad on three occasions swears by it (Surahs lxxiv. 35; lxxxiv. 18; xci. 2), and it is said to have been set in the heavens for a light (Surahs x. 5; lxxi 15), to run to its appointed goal (Surahs xxxv. 14; xxxix. 7), and that it will be eclipsed at the Day of Judgment (Surah lxxv. 8). The LIVth Surah of the Qur’an, which is entitled the Suratu ‘l-Qamar, begins with a reference to the splitting of the moon, which is a matter of controversy. It reads: “The hour draws nigh and the moon is split asunder. But if they see a sign, they turn aside and say magic continues.”
Al-Baizawi refers it to a miracle, and says the unbelievers having asked Muhammad for a sign. the moon appeared to be cloven in twain. But the most natural explanation of the passage is, that the expression refers to one of the signs of the Resurrection.
At an eclipse of the moon, a devout Muslim is expected to recite a two rak’ah prayer.
Based on Hughes, Dictionary of Islam