The words "taʾwil" and "tafsir" both mean roughly "explanation, elucidation, interpretation, and commentary"; but from the end of the 8th century CE onwards, "taʾwil" 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 Shia and Sunni 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.