The word(s) "as-sunnah" appears 3 time(s) in 3 verse(s) in Quran in Mohsin Khan translation.

(1) Or do they envy men (Muhammad صلى الله عليه وسلم and his followers) for what Allah has given them of His Bounty? Then We had already given the family of Ibrahim (Abraham) the Book and Al-Hikmah (as-sunnah - Divine Revelation to those Prophets not written in the form of a book), and conferred upon them a great kingdom.

(2) And during a part of the night (also) glorify His praises (i.e. Maghrib and 'Isha prayers) and (so likewise) after the prayers [as-sunnah, Nawafil - optional and additional prayers. And also glorify, praise and magnify Allah - Subhan Allah, Alhamdu lillah, Allahu-Akbar].

(3) He it is Who sent among the unlettered ones a Messenger (Muhammad صلى الله عليه وسلم) from among themselves, reciting to them His Verses, purifying them (from the filth of disbelief and polytheism), and teaching them the Book (this Qur'an, Islamic laws and Islamic jurisprudence) and Al-Hikmah (as-sunnah: legal ways, orders, acts of worship of Prophet Muhammad صلى الله عليه وسلم). And verily, they had been before in manifest error;