The purpose of this paper is to clarify the meaning of the στoιχϵῖoν in Aristotle’s Rhetoric. First, we review several texts of the Rhetoric in which this word is used, and examine the interpretations of Grimaldi and Horio. In this paper, I reject Grimaldi’s interpretation and follow Horio’s interpretation which shows the στoιχϵῖoν in the Rhetoric to have two meanings. Next, we examine the examples of stoiqeῖon in the Topics and clarify the meaning of this word. In the Topics, the στoιχϵῖoν means the rule or principle to be common to many topos. Finally, we clarify the meaning of the στoιχϵῖoν in the Rhetoric from the meaning of the στoιχϵῖoν in the Topics. This paper concludes that the meaning of the στoιχϵῖoν of the first volume and the second volume in the Rhetoric is different. the στoιχϵῖoν in the first volume of Rhetoric means the basic definition of “species.” In the second volume, on the other hand, Aristotle calls the rules or principles which are common to many arguments as koinoi topoi. Several instances of these rules or principles (koinoi topoi) are the same as some topoi in the Topics.広島大学比較論理学プロジェクト研究センター研究成果報告書（2019年度
