The word(s) "day" appears 568 time(s) in 513 verse(s) in Quran in Muhammad Pickthal translation.

(341) Lo! We verily do help Our messengers, and those who believe, in the life of the world and on the day when the witnesses arise,

(342) The day when their excuse availeth not the evil-doers, and theirs is the curse, and theirs the ill abode.

(343) Allah it is Who hath appointed for you night that ye may rest therein, and day for seeing. Lo! Allah is a Lord of bounty for mankind, yet most of mankind give not thanks.

(344) Say (O Muhammad, unto the idolaters): Disbelieve ye verily in Him Who created the earth in two days, and ascribe ye unto Him rivals? He (and none else) is the Lord of the Worlds.

(345) He placed therein firm hills rising above it, and blessed it and measured therein its sustenance in four days, alike for (all) who ask;

(346) Then He ordained them seven heavens in two days and inspired in each heaven its mandate; and We decked the nether heaven with lamps, and rendered it inviolable. That is the measuring of the Mighty, the Knower.

(347) Therefor We let loose on them a raging wind in evil days, that We might make them taste the torment of disgrace in the life of the world. And verily the doom of the Hereafter will be more shameful, and they will not be helped.

(348) And (make mention of) the day when the enemies of Allah are gathered unto the Fire, they are driven on

(349) That, your thought which ye did think about your Lord, hath ruined you; and ye find yourselves (this day) among the lost.

(350) And of His portents are the night and the day and the sun and the moon. Do not prostrate to the sun or the moon; but prostrate to Allah Who created them, if it is in truth Him Whom ye worship.