Its plural is Saha'if or Suhuf as the Almighty says...

Its plural is Saha'if or Suhuf as the Almighty says; "'Suhuf' of Abraham and Moses, and also...receiving pure 'Suhuf' (pages) wherein are all the correct books." Holy Qur'an (87:19) It is said that it means the Qur'an and that by using the plural Suhuf in which are 'Books', it is meant to say that they include more than what is in Allah's Books.

Hence, a Mashaf is a collection of written Suhuf, and its plural form is Masahif.(36) Therefore, the word Mashaf means any book and is not a special term for "the Book of Allah". It can mean any collection of Suhuf (leaves of paper or skin), and only in this context can the Qur'an also be called Mashaf because it is a collection of Suhuf. The exclusive names for the Book of Allah are: Al-Qur'an, al-Dhikr, al-Furqan and al-Kitab(37), as mentioned in the holy text, itself.

Allah did not call it "Mashaf", but, it were the later Muslims who named it so, after having compiled it on leaves or sheets. Thus, it is clear that the mistake arose from the linguistic use of the word during the early days of Islam, when people did not take 'Mashaf'…