This gets to an interesting issue. In Syriac Christianity, the "Qeryana" is a selection of scripture that you read to the congregation (like a selection of verses from the Gospel of Matthew, for example). The scripture would never refer to itself as Qeryana, since that's a liturgical term. But the Qur'an uses a derivative of that Syriac term totally differently! When it says "Qur'an," it seems to be referring to itself, as a *commentary* on older scripture, or a confirmation of it. How could that happen? Well, I think the most likely explanation is that the Qeryana was in Syriac (since Christian scripture was not translated into Arabic until very late), delivered to an Arabic-speaking audience with commentary in Arabic vernacular. That Arabic commentary would have talked about the "Qur'an", referring to the Syriac scripture that had just been read, or was about to be read, explaining it in 'clear Arabic.' But the Qur'an became understood as referring to the scriptural commentary itself, rather than the Biblical reading, which then became understood as if it, in turn, was scripture.
Now the interesting thing is that the original meaning of Qur'an does not seem to have been preserved, or it is not clearly preserved. In Q 85, it ends by saying "This is an honored Qur'an, in a preserved state." But the immediately preceding lines say "Has there reached you the story of the soldiers - [Those of] Pharaoh and Thamud? But they who disbelieve are in [persistent] denial, While Allah encompasses them from behind. But this is an honored Qur'an [Inscribed] in a Preserved Slate." This can be read as a reference to written scripture (i.e. the Bible), which is called the Qur'an, which would be consistent with the Syriac Christian use of the term Qeryana to mean portions of the bible. Similarly 84:21: "And when the Qur'an is recited to them, they do not prostrate [to Allah ]?" Islamic tradition assumes that the Qur'an here means the recitation being given ... but you could just as easily interpret this reference as meaning a reading of the Syriac Biblical scripture.
So my thinking is that Qur'an probably originally meant the Syriac scripture, but then the Arabic commentary on that scripture was seen as a repetition of the scripture's meaning (essentially like a translation or paraphrased explanation), and ascribed holiness, thus itself being Qur'an (which you could call an Arabic translation or commentary on Syriac scripture).
Topic: Qur'anic studies today