This article aims at clarifying this point that from the root (v-l-y: ی-ل-و (only two meanings can be inferred: first, "closeness " or being continuous and behind each other. Second, “guardianship” , being allowed to manage one’s life, and being a commanding officer and so on . After these two meanings have been proven regarding the root of vali, we express (vali) in the form of فعیول has only been heard in the second meaning, and therefore, this word has no meaning other than guardianship and one allowed to manage. Other meanings of this word have been justified in the following and we believe that the other meanings that have been mentioned for it are either examples of the meaning of guardian or the requirements of it. The result that can be obtained from this article directly plays a role in the use of Shia texts on the Imamate of Hazrat Ali, such as the verse of vilayat and Hadith Ghadir; because if the word vali ولوی and Mulla مووال mean only one thing, there will be no doubt about the meaning of these texts .