The word(s) "three" appears 20 time(s) in 19 verse(s) in Quran in Muhammad Habib Shakir translation.

(1) And accomplish the pilgrimage and the visit for Allah, but if, you are prevented, (send) whatever offering is easy to obtain, and do not shave your heads until the offering reaches its destination; but whoever among you is sick or has an ailment of the head, he (should effect) a compensation by fasting or alms or sacrificing, then when you are secure, whoever profits by combining the visit with the pilgrimage (should take) what offering is easy to obtain; but he who cannot find (any offering) should fast for three days during the pilgrimage and for seven days when you return; these (make) ten (days) complete; this is for him whose family is not present in the Sacred Mosque, and be careful (of your duty) to Allah, and know that Allah is severe in requiting (evil).

(2) And the divorced women should keep themselves in waiting for three courses; and it is not lawful for them that they should conceal what Allah has created in their wombs, if they believe in Allah and the last day; and their husbands have a better right to take them back in the meanwhile if they wish for reconciliation; and they have rights similar to those against them in a just manner, and the men are a degree above them, and Allah is Mighty, Wise.

(3) He said: My Lord! appoint a sign for me. Said He: Your sign is that you should not speak to men for three days except by signs; and remember your Lord much and glorify Him in the evening and the morning.

(4) When you said to the believers: Does it not suffice you that your Lord should assist you with three thousand of the angels sent down?

(5) And if you fear that you cannot act equitably towards orphans, then marry such women as seem good to you, two and three and four; but if you fear that you will not do justice (between them), then (marry) only one or what your right hands possess; this is more proper, that you may not deviate from the right course.

(6) O followers of the Book! do not exceed the limits in your religion, and do not speak (lies) against Allah, but (speak) the truth; the Messiah, Isa son of Marium is only an apostle of Allah and His Word which He communicated to Marium and a spirit from Him; believe therefore in Allah and His apostles, and say not, three. Desist, it is better for you; Allah is only one Allah; far be It from His glory that He should have a son, whatever is in the heavens and whatever is in the earth is His, and Allah is sufficient for a Protector.

(7) Certainly they disbelieve who say: Surely Allah is the third (person) of the three; and there is no god but the one Allah, and if they desist not from what they say, a painful chastisement shall befall those among them who disbelieve.

(8) Allah does not call you to account for what is vain in your oaths, but He calls you to account for the making of deliberate oaths; so its expiation is the feeding of ten poor men out of the middling (food) you feed your families with, or their clothing, or the freeing of a neck; but whosoever cannot find (means) then fasting for three days; this is the expiation of your oaths when you swear; and guard your oaths. Thus does Allah make clear to you His communications, that you may be Fateful.

(9) And to the three who were left behind, until the earth became strait to them notwithstanding its spaciousness and their souls were also straitened to them; and they knew it for certain that there was no refuge from Allah but in Him; then He turned to them (mercifully) that they might turn (to Him); surely Allah is the Oft-returning (to mercy), the Merciful.

(10) But they slew her, so he said: Enjoy yourselves in your abode for three days, that is a promise not to be belied.