The Definition of The Qur’an..

Scholars define the Qur’an as this: The Arabic speech of Allah that was revealed to the Prophet (PBUH) both in word and in meaning. It is collected between the two covers of the mushaaf, was narrated in mutawaatir chains, and is a challenge to humankind.
We can learn five important things about the Qur’an from this definition.
1. The Arabic speech of Allah: The Qur’an is the speech of Allah, in Arabic. This means that anything that’s not Arabic isn’t the Qur’an. You can’t pray in English, in French, in Swahili, in Urdu–it have to be in Arabic.
2. Revealed to the Prophet: We know that Allah revealed many revelations–including the Injeel and the Taw rah and the Zabur. Those are also revelation of Allah–but they’re not the Qur’an. Only what Allah revealed to the Prophet (PBUH) is Qur’an.
3. Revealed in Word and Meaning: Not Only is the meaning of the Qur’an the same as what Allah meant; but the words themselves are also from Allah. (Unlike Hadith Qudsi, where the meaning is from Allah, and the words are from the Prophet (PBUH)
4. Collected between Two Covers: Hadith Qudsi is also the speech of Allah, but it’s not Qur’an. Similarly, there are verses that used to be in the Qur’an, but aren’t anymore–even though they were once! These are the abrogated verses, and they’re not considered Qur’an anymore, even though we still know what some of those revelations were.
5. Mutawaatir: The Qur’an was related in a mutawaatir fashion–so many narrators narrated it, at every single step in the chain of narration, that it’s impossible that they all lied or made a mistake.
6. A Challenge to Humankind: The Qur’an is an ongoing challenge to the human race–create a book, a surah, a verse like it; but nay, we will NEVER be able to. Allah Himself says so.
One other important part of the definition of the Qur’an is that Allah promised that He will protect it, until the end of time–and that promise doesn’t apply to anything else (such as the sunnah, or the Hadith Qudsi).
And you thought you knew the Qur’an!
May Allah allow us all to become saahibul-Qur’an, Companions of the Qur’an, those whom Allah will give the highest level of jannah (ameen)!
References
Yasir Qadhi. Lecture. AlMaghrib. Route 114: Qur’anic Sciences. University of Toronto, Scarboro.