The Quran is the holy book of Islam — the book Muslims believe God (Allah) revealed to the Prophet Muhammad. In English we say the Quran the way we say the Bible: a name for that scripture. You will also see Qur’an, and in older English Koran; same book, different spellings. Muslims treat the Arabic text as the word of God; translations help people understand, but the Arabic is the one used in prayer. It is recited aloud, taught from childhood, and handled with care. Though actually, “Muslim Bible” is a shortcut some English speakers use, and it can sound careless: it is its own book, in its own language, with its own place in the faith. Use Quran (or Qur’an), and give it that name.