The word(s) "back" appears 101 time(s) in 98 verse(s) in Quran in Muhammad Pickthal translation.

(91) His is the Sovereignty of the heavens and the earth, and unto Allah (all) things are brought back.

(92) On the day when the hypocritical men and the hypocritical women will say unto those who believe: Look on us that we may borrow from your light! it will be said: Go back and seek for light! Then there will separate them a wall wherein is a gate, the inner side whereof containeth mercy, while the outer side thereof is toward the doom.

(93) Those who put away their wives (by saying they are as their mothers) and afterward would go back on that which they have said, (the penalty) in that case (is) the freeing of a slave before they touch one another. Unto this ye are exhorted; and Allah is Informed of what ye do.

(94) O ye who believe! When believing women come unto you as fugitives, examine them. Allah is Best Aware of their faith. Then, if ye know them for true believers, send them not back unto the disbelievers. They are not lawful for them (the disbelievers), nor are they (the disbelievers) lawful for them. And give them (the disbelievers) that which they have spent (upon them). And it is no sin for you to marry such women when ye have given them their dues. And hold not to the ties of disbelieving women; and ask for (the return of) that which ye have spent; and let them (the disbelievers) ask for that which they have spent. That is the judgment of Allah. He judgeth between you. Allah is Knower, Wise.

(95) Then, when they have reached their term, take them back in kindness or part from them in kindness, and call to witness two just men among you, and keep your testimony upright for Allah. Whoso believeth in Allah and the Last Day is exhorted to act thus. And whosoever keepeth his duty to Allah, Allah will appoint a way out for him,

(96) Unto him of you who will advance or hang back.

(97) But whoso is given his account behind his back,

(98) Which weighed down thy back;