Esoteric interpretation of the Quran, also known as Sufi interpretation and taʾwīl (تأويل), is the allegorical interpretation of the  Quran or the quest for its hidden, inner meanings. It was a synonym of conventional interpretation in its earliest use, but it came to mean a process of discerning its most fundamental understandings. Esoteric interpretations do not usually contradict the conventional (in this context called exoteric) interpretations; instead, they discuss the inner levels of meaning of the Quran. The words Ta'wil and Tafsir have been translated to mean explanation, elucidation, interpretation, and commentary; but from the end of the 8th century onwards, 'ta'wil' was commonly regarded as the esoteric or mystical interpretation of the Quran, while the conventional exegesis of the Quran was called "tafsir". The term batin refers to the inner or esoteric meaning of a sacred text, and zahir to the apparent or exoteric meaning. Esoteric interpretations are found in Sufi, Shia, Sunni, and Baha'i interpretations of the Quran. A hadith which states that the Quran has an inner meaning, and that this inner meaning conceals a yet deeper inner meaning, and so on (up to seven successive levels of deeper meaning), has sometimes been used in support of this view.