The word(s) "eighty" appears 3 time(s) in 3 verse(s) in Quran in Abdullah Yusuf Ali translation.

(1) Say: "What thing is most weighty in evidence?" Say: "Allah is witness between me and you; This Qur'an hath been revealed to me by inspiration, that I may warn you and all whom it reaches. Can ye possibly bear witness that besides Allah there is another Allah?" Say: "Nay! I cannot bear witness!" Say: "But in truth He is the one Allah, and I truly am innocent of (your blasphemy of) joining others with Him."

(سورة الأنعام, Al-An'aam, Chapter #6, Verse #19)
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(2) And those who launch a charge against chaste women, and produce not four witnesses (to support their allegations),- flog them with eighty stripes; and reject their evidence ever after: for such men are wicked transgressors;-

(سورة النور, An-Noor, Chapter #24, Verse #4)
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(3) Soon shall We send down to thee a weighty Message.

(سورة المزمل, Al-Muzzammil, Chapter #73, Verse #5)
(Arabic, Transliteration, Urdu (Ahmed Ali), Urdu (Jalandhry), Farsi, Yusuf Ali, Shakir, Picthal, Mohsin Khan, French, Spanish, Indonesian, Malay, German, Bosnian, Russian, Dutch, Italian, Portuguese, Tafsir - Jalal ad-Din, Tafsir - King Fahad Quran Complex)