In both Persian and Russian, noun can play a very major role in the syntactic construction of a sentence. The function of noun in a sentence depends upon the effect of words. Persian linguists, taking into consideration the importance of nouns have allotted different roles and functions to it. Generally these roles from the view point of definition fit within a framework. Normally, for the function of nouns the same types of nouns are used, this refrains the reader from getting confused over the understanding of its different roles. Persian linguists differ in their views about the various functions of nouns. Five scholars consider four functions of noun within a sentence: nominative, accusative, genitive, and vocative. Dr. Khampur believes that nouns can have up to thirteen functions. Other scholars consider either more functions or less.