The word(s) "trinity" appears 2 time(s) in 2 verse(s) in Quran in Mohsin Khan translation.

(1) O people of the Scripture (Christians)! Do not exceed the limits in your religion, nor say of Allah aught but the truth. The Messiah 'Îsa (Jesus), son of Maryam (Mary), was (no more than) a Messenger of Allah and His Word, ("Be!" - and he was) which He bestowed on Maryam (Mary) and a spirit (Ruh ) created by Him; so believe in Allah and His Messengers. Say not: "Three (trinity)!" Cease! (it is) better for you. For Allah is (the only) One Ilah (God), glory be to Him (Far Exalted is He) above having a son. To Him belongs all that is in the heavens and all that is in the earth. And Allah is All-Sufficient as a Disposer of affairs.

(2) Surely, disbelievers are those who said: "Allah is the third of the three (in a trinity)." But there is no Ilah (god) (none who has the right to be worshipped) but One Ilah (God -Allah). And if they cease not from what they say, verily, a painful torment will befall on the disbelievers among them.