Qur'an 39:23 makes it clear that there is a mesani / mesaniy and Qur'an, and they are separate:
:39.23 Allah has revealed (from time to time) the most beautiful Message in the form of a Book, consistent with itself, (yet) repeating (its teaching in various aspects): the skins of those who fear their Lord tremble thereat; then their skins and their hearts do soften to the celebration of Allah's praises. Such is the guidance of Allah: He guides therewith whom He pleases, but such as Allah leaves to stray, can have none to guide.
The main text makes it clear that something, a book or a text called mesaniy / mesani were given to Mohamed (pbuh).
:15.87 And We have bestowed upon thee the Seven Oft-repeated (verses) and the Grand Qur'an.
Which implies that there were seven laws before the giving of the Qur'an. It is generally accepted that "saban minel masani" (Seven Oft-repeated verses) and "quranel azim" (Grand Reading/Qur'an) must be two different things because they are separated with conjunction waw. However many Islamic scholars are at a loss to defined what the Mesani is. The proposal that they are the seven laws of Noah has been found acceptable by those muslims who have thought about it.