A part of Ibne Hesams Innovations in Riyaz Alftyan (Appellation and lexical differences)

"Riyaz Alftyan", The best commentaries of "Nesabossebyan" was written in Teimurian period.However,"Riyaz Alftyan" and its writer have not been introduced up to now. The main issue in this paper is to introduce it and itʾs author and a part of his innovation concerning mentioning the appellation and differences of the words. The results of the present study obtained through a descriptive analysis procedure and on the basis of documentary method show that Nezamoddin Ibne Kamaloddin Ibne Jamoloddin Khafi Heravi known as Ibne Hesam Heravi is the philologist of the Teimurian age and his "Riyaz Alftyan" as an educational text is the oldest and most comprehensive commentaries of "Nesabossebyan". His masterpiece is a good reference for understanding the lexical differences which are apparently synonymous and for the appllation of some Arabic lexis.