Many researchers believe that the time to explore the Persian words in Arabic books has come to an end because their predecessors have already said what should be said. Although the efforts of the predecessors in this regard are commendable, there is much to be studied yet. This article tries to argue that some Persian words, despite being used in Arabic texts, are mentioned neither in Arabic dictionaries nor in books related to “arabization.” Moreover, what is expressed about definition and explanation of some Persian words is inexpressive and imperfect. In the present article, we demonstrate that dictionaries have not included “Al-Bārjin” which is a Persian word used in Arabic books. Also the definitions given for “Al-Xordādhi” are incomplete. Two points should be mentioned here: first, in this paper, in order to understand how to use the expressed words, instead of merely analyzing lexical works, various sources from different fields have been examined. These include historical, geographical, and literary books as well as religious books such as jurisprudential and hadith works. Second, such research should not, by definition, be considered a linguistic “entertainment.” And we should not think that it is useless to find the meaning of ancient words that are no longer used in Persian or Arabic today because such research has historical and cultural importance in addition to lexical value; it discusses the interaction of the two languages which is one of the aspects of the relations between Iranians and Arabs. The choice of these two words is due to the fact that they come from the daily life of the people; Al-Bārjin was a tool for eating, and Al-Xordādhi referred to the wine and its container. Words like these in Arabic are evidence of the infiltration of Iranians into the Arabic-Islamic way of life.