The word(s) "once" appears 85 time(s) in 79 verse(s) in Quran in Muhammad Habib Shakir translation.

(61) And those who were deemed weak shall say to those who were proud. Nay, (it was) planning by night and day when you told us to disbelieve in Allah and to set up likes with Him. And they shall conceal regret when they shall see the punishment; and We will put shackles on the necks of those who disbelieved; they shall not be requited but what they did.

(62) Except him who snatches off but once, then there follows him a brightly shining flame.

(63) Then he looked at the stars, looking up once,

(64) None dispute concerning the communications of Allah but those who disbelieve, therefore let not their going to and fro in the cities deceive you.

(65) (Of) the day when they shall come forth, nothing concerning them remains hidden to Allah. To whom belongs the kingdom this day? To Allah, the One, the Subduer (of all).

(66) He knows the stealthy looks and that which the breasts conceal.

(67) Those who dispute concerning the communications of Allah without any authority that He has given them; greatly hated is it by Allah and by-those who believe. Thus does Allah set a seal over the heart of every proud, haughty one.

(68) Surely they who deviate from the right way concerning Our communications are not hidden from Us. What! is he then who is cast into the fire better, or he who comes safe on the day of resurrection? Do what you like, surely He sees what you do.

(69) And they did not become divided until after knowledge had come to them out of envy among themselves; and had not a word gone forth from your Lord till an appointed term, certainly judgment would have been given between them; and those who were made to inherit the Book after them are most surely in disquieting doubt concerning it.

(70) Those who do not believe in it would hasten it on, and those who believe are in fear from it, and they know that it is the truth. Now most surely those who dispute obstinately concerning the hour are in a great error.