The word(s) "back" appears 225 time(s) in 216 verse(s) in Quran in Abdullah Yusuf Ali translation.

(101) Or do ye feel secure that He will not send you back a second time to sea and send against you a heavy gale to drown you because of your ingratitude, so that ye find no helper. Therein against Us?

(102) Say: "If the whole of mankind and Jinns were to gather together to produce the like of this Qur'an, they could not produce the like thereof, even if they backed up each other with help and support.

(103) What kept men back from belief when Guidance came to them, was nothing but this: they said, "Has Allah sent a man (like us) to be (His) Messenger?"

(104) Say: "If ye had control of the Treasures of the Mercy of my Lord, behold, ye would keep them back, for fear of spending them: for man is (every) niggardly!"

(105) Thou wouldst have deemed them awake, whilst they were asleep, and We turned them on their right and on their left sides: their dog stretching forth his two fore-legs on the threshold: if thou hadst come up on to them, thou wouldst have certainly turned back from them in flight, and wouldst certainly have been filled with terror of them.

(106) "Nor do I deem that the Hour (of Judgment) will (ever) come: Even if I am brought back to my Lord, I shall surely find (there) something better in exchange."

(107) And what is there to keep back men from believing, now that Guidance has come to them, nor from praying for forgiveness from their Lord, but that (they ask that) the ways of the ancients be repeated with them, or the Wrath be brought to them face to face?

(108) Moses said: "That was what we were seeking after:" So they went back on their footsteps, following (the path they had come).

(109) He said: "Whoever doth wrong, him shall we punish; then shall he be sent back to his Lord; and He will punish him with a punishment unheard-of (before).

(110) "Behold! thy sister goeth forth and saith, 'shall I show you one who will nurse and rear the (child)?' So We brought thee back to thy mother, that her eye might be cooled and she should not grieve. Then thou didst slay a man, but We saved thee from trouble, and We tried thee in various ways. Then didst thou tarry a number of years with the people of Midian. Then didst thou come hither as ordained, O Moses!