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‎الشِّعْبُ : الطَّرِيقُ فِي الجَبَلِ
‎الشِّعْبُ : الوَادِي الصَّغِيرُ بَيْنَ جَبَلَيْنِ
الجمع : شِعاب
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Another translation: the people of Makkah best know its streets.
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This expression is often used when acknowledging or describing “insider knowledge”