The word(s) "trinity" appears 2 time(s) in 2 verse(s) in Quran in Abdullah Yusuf Ali translation.

(1) O People of the Book! Commit no excesses in your religion: Nor say of Allah aught but the truth. Christ Jesus the son of Mary was (no more than) a messenger of Allah, and His Word, which He bestowed on Mary, and a spirit proceeding from Him: so believe in Allah and His messengers. Say not "trinity": desist: it will be better for you: for Allah is one Allah: Glory be to Him: (far exalted is He) above having a son. To Him belong all things in the heavens and on earth. And enough is Allah as a Disposer of affairs.

(سورة النساء, An-Nisaa, Chapter #4, Verse #171)
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(2) They do blaspheme who say: Allah is one of three in a trinity: for there is no god except One Allah. If they desist not from their word (of blasphemy), verily a grievous penalty will befall the blasphemers among them.

(سورة المائدة, Al-Maaida, Chapter #5, Verse #73)
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